Not sure whether to have hope or not :(

[imsickbutimpretty]

Hi all. Really sorry that this is my first post but I'm going out of my mind.
Went for an early scan should be 9 + 3. Had an external and internal.
Showed a sac, yolk sac and fetal pole. Fetal pole CRM is 4mm (altho also on the report as 4.2 so not sure?). Mean sac measurement is 21mm. They didn't see a heartbeat at this point.I don't know anything about sac measurements so don't know what I;m looking for and what's a red flag.

Because I told them I was regular (thought I was!) they said they don't think this is going to be viable as they would expect it to be measuring bigger.
Didn't realise. but when I actually went thru my diary when I got home (we weren't trying so hadn't been tracking or anything) realised my cycles vary between 25 days and 41 days.
I took a test the day after I thought my period was due but realised it could have actually been up to 5 days before period was due (used a first response as I had sore boobs and had had unprotected sex with DP).
I also had Norovirus the week before I took the test so not sure if that could affect anything. I'm sure of when I had sex - 24th October and I took a test on the 13th November but not sure when I would have ovulated as I don't track.
I guess this is a really long and roundabout way of asking if my dates could actually be behind and if I should tell the EPU that my cycles actually haven't been regular at all or whether this won't make any difference to them?
Have another scan. on the 28th of December to see if there has been any growth so they haven't said definitely but the scanner did talk me through my MC options so I just don't know what to think now.
Sorry for the long post I suffer anxiety anyway and I am sick with it getting myself really scared about MC but not even sure if it's going to happen. I've been going over and over my dates on the calendar but (I know this sounds pathetic) I don't fully get how cycles work so I don't know if my irregular cycles can affect my date sbecause surely it's about the day I had sex.
Sorry but please don't read and run any advice would be so appreciated right now.

Really sorry you're going through this. The wait is awful.

It does sound more likely that it will be a mc

Thank you for answering and being honest.
I am devastated I was really hoping some people had been in a similar situation and had a happy ending.
My cycles being out made me have such hope that my dates could somehow be miraculously late or that maybe it will have grown by the time I go back :( Christmas is going to be impossible.

bump...anyone got any positive stories at all? :(

I'm so sorry OP but it doesn't sound good. Based on your dates, you'd really be expecting to see more than you did by now. I know it's impossible not to hold on to that tiny shred of hope, but I'd be preparing for the worst case scenario if I were you
It is the shittiest, most utterly unfair thing. But you can and will get through it. I've had 2 mmc, first discovered at a scan at 13w and second at 11w. Feels like the end of the world, but somehow you survive the days, and sooner or later you'll be able to truly smile again. You never forget, but you learn to live with it. And you can try again, when you feel up to it.

Just sending some love. I'm in a similar boat myself (8 weeks by dates but backdated on the scan I had the other week) and also suffered a MMC two years ago. We have no idea how things will turn out for us and it will be a long wait til your next scan. All you can do is keep really busy and try to stay off google until you know the outcome. Fingers crossed for you, there are happy stories that begin like this too x