To be furious at my ‘supposedly’ best friend?

In the nicest possible way - you were expecting to be MOH but missed out and got bridesmaid. Whilst you can having disappointed feeling about missing out on the top job, being bereft is going down the dramatic route

dust yourself down and accept you are included in the. bridal party and enjoy the wedding, without having to juggle the responsibility of the arrangements and two children.

Im sure that you will have a lovely day, relaxed as the event admin falls to someone else.

In that case I think she will be even more appreciative of your help. You can still help if you are not close, you only need her phone number to start a conversation.

It wasn't really disingenuous as the OP didn't have a sister who could do the role?

I get why you are upset. It might seem trivial but she’s been a bit disingenuous taking the MOH role for your wedding and then basically demoting you for her own wedding.

I do think sisters tend to be MOH but it’s not exactly a surprise she has one so if that was going to be the case then she should have been upfront. The doing it cos you’re pregnant bit is weird. Surely it would be up to you to let her know if it was too much due to however you are finding pregnancy. Step back from the planning and let her and her sister sort out the details then.

My best friend and I were going to join the navy together. Neither of us did. Probably why we aren't best friends 50 years later.

You are a bridesmaid! Its a huge honour.

I cannot imagine anything worse than planning and attending a hen do or helping to organise and be in a wedding while pregnant or with a new baby. She has kindly spared you, which one day you’ll be grateful for once you understand how hard it is to have a baby.

Ah, for fucks sake, grow up.

OP, you are sounding quite needy now.
Put yourself out of your comfort zone and offer to help her sister if she would like that. If she doesn’t respond positively at least you have tried. Why does her being younger make any difference.
That’s what being a good friend is all about.

Be happy for your friend, reach out and let her know you are delighted to be a bridesmaid and will do anything to help, wherever it’s needed. And you only wish her the best for the day.
Your friend has done nothing wrong.
You shouldn’t feel wronged by her. It’s that feeling you have of being wronged which won’t serve you well unless you nip it in the bud asap.

The chief bridesmaid is literally the oldest unmarried woman attending the bride who's over flowergirl age. Once you're married, you're a matron of honour. Assuming you'll have a hand in organising stuff and be dressed as a bridal party member, what difference is it actually going to make? Will anyone at the wedding even know? These titles aren't really bestowed, they're just dealt according to age and whether you're married or not.

You're bereft? Come the fuck on. Honestly, you're going to be a parent. It's a good time to realise you're an adult and act like it.

Yep. Apparently that makes all the difference.

This ^^^

I'm sure her sister will appreciate any help and you can show off your planning skills

What did I miss? Oh the deal was made in secondary not primary? Hardly warrants an eye roll.

Sorry but a sister comes before a friend, however good a friend you are.

Did her sister know about the deal? Did you pinky promise? Presumably you can still help with the hen do and you will be an important part of the wedding. Do you have a sister that could have been MOH, if so how did she take being demoted? If not you didn't have the problem.

Have you expressed your feelings to your best friend? It's understandable how you are feeling but maybe her sister made her feel bad and did what she had to....talk it through with her and accept her decision.you will always be her best friend so don't go ruining your friendship over this. Just enjoy her big day and be supportive.

I am so sad and feel bereft in a way I’m never going to have the chance of being ‘chief bridesmaid’

Honestly, it's an awful job.

Oh, for goodness sake, get a grip of yourself. If you love planning so much, then throw a party. Your friend does not owe you the planning of her hen/wedding.

Genuinely what is the difference between a maid of honour and bridesmaids? No wedding I've been part of had ever made the distinction

What were you expecting/wanting to do that you think is no longer open to you?

I found out that I will be a bridesmaid whilst her sister is the maid of honour.
It's normal that a sister would be MOH. Times change and life moves on and just because you made a deal when you were young doesn't mean that you both have to stick to it. Circumstances change.

I might be overreacting but I am quite upset and frankly furious
Yes you are massively overreacting.

I thought we knew each other better than this and I don’t know if the relationship will ever be the same tbh. I was even more heartbroken when she said that the reason behind this snub is the fact that I am pregnant and would not be able to put 100% effort into wedding planning
Her reasoning is fair enough. There might be other reasons but that's the one she's chosen to tell you.
"Heartbroken" is a total overreaction to this.

.

Three choices, ok four choices

You accept the role of bridesmaid , celebrate with your friend on her big day and thank goodness that you are pregnant so can get out of any of the worst hen night stuff.

you accept the role of bridesmaid, complain the dress makes you look like a whale, turn up with a face like thunder , scowl in all the pictures and accidentally tread on the brides dress going up the aisle.

You throw a wobbly, refuse to have anything to do with the wedding including being a guest and spend the rest of the year in tears and forever regret losing the friendship over such a silly reason.

You say you can’t take on the role of BM due to family commitments but look forward to attending the wedding and celebrating with her because you are each other’s oldest friends and you appreciate her concern for your pregnancy because she knows how upset you would be if you had to let her down at the last minute.

I haven't read all the replies only yours OP so it may have already been suggested, but if I was you I would contact the sister and offer to help her with the planning and preparations. That way you will still be involved and I'm sure she will be glad of the assistance.

You are being ridiculous.