Ah OP right now must be so hard for you and you have the sympathies of this internet stranger.
I can’t tell you what is right, nobody else really can. But when faced with a situation where I had to decide between keeping a pregnancy or terminating I was in such an emotional flux that I was certain I should carry on one moment to certain I should terminate in the next moment.
I sat down when my twins were in bed and I had some quiet to really envision life with 3 under 5, with the good and the bad another baby would bring into the mix - especially as my twins weren’t yet 1 when I discovered I was pregnant again.
I decided to keep baby 3 after a lot (and I mean a LOT) of soul searching; what impact would baby 3 have on my twins, on me, on finances and on my relationship with DH (who didn’t want to go ahead).
In the end I looked at the online material for terminations, as soon as I started to read I felt sick and couldn’t stop crying, that’s when I knew that come hell or high water, I personally couldn’t terminate. Unfortunately baby 3 wasn’t meant to be, but I spent a lot of time being “logical” and considering each and every part of my life at that point and theorised how I might make baby 3 fit with that. In the end my emotions let me know for sure what decision was right for me.
Don’t rush yourself into a decision and either way, you are not being selfish, just remain as honest as you can with yourself about what changes another baby will bring and go from there. Do what is right for you and your DC.
I was told I would very likely never conceive after I was finally diagnosed with endometriosis which resulted in a Fallopian tube and Ovary being removed from my body and it was a few months after (when my doctors were still considering a full hysterectomy due to the damage endometriosis has caused over years of not being diagnosed) I fell pregnant with my twins.
So whilst you may have been previously advised it could be difficult for you, you have physical evidence that you can and whilst I really do understand the temptation to keep going with this pregnancy in case it’s your last chance, nobody can know that this will be so, as hard as it is, please keep that in mind when you make the decision that is right for you.
I wish you well @confusedmumof1 and all the best 