I am literally incapable of sticking to decisions

[swizzlestickss]

I struggle to make decisions and also stick with them, and it’s honestly really starting to bother me!

Today’s example, tonight I would usually (every Tuesday night) be going to a pub quiz with my friends. The pub is near my parents so I’ll usually pop round for dinner before this.

Last night, I knocked my head on a cupboard and today I felt really dizzy and had a bad headache so I called in sick to work. Went to my GP who told me I have mild concussion. He advised I should stay in bed for the next few days.
He also advised me not to work for the rest of the week, but I don’t get paid so I’ve already decided against that!

My problem is, I decided earlier I can’t go to the pub quiz with loud music, and I should stay at home and rest.
But now my headache has slightly gone down and I’m already thinking of changing my mind. That I’m being dramatic, my headache isn’t that bad, my parents will feel let down and it’s not a very good excuse now it’s gone down.
I also feel boring if I cancel on the quiz, i already have a few times recently because I’ve struggled with my mental health a little bit.

So I suppose my problem is how do I stop being so indecisive and belittling my own decisions for sake of everyone else?! I’ve always been like this and it’s so easy to say “think about yourself” but I can never apply it

It is a mild concussion, concussion! Not just a headache.
And the doctor told you to rest, even not to work.
So there is no any scope for you to go out today. Nil.

It’s actually not your decision, it’s medical advice.

Stay in bed.

Surely your parents would understand? And your friends?

Concussions are serious, even if your symptoms have subsided. It's not for no reason that they are now referred to as "traumatic brain injuries". I work in a school and it is well-nigh impossible to convince some pupils, and their parents sometimes, to take a knock to the head seriously. It takes about three to four weeks to recover, even if you feel fine, because the brain needs to right itself again, and that takes a lot of rest, low screen time, and not too much work or over-stimulation. Recovery can take longer or become more complex if you don't treat it with respect.

So this is a clear "No." If you struggle to say no even with all of this, then I would suggest therapy to help you strengthen your boundaries, because you are compromising yourself into risk in this one instance, which means you may well do it again.