I am so sorry to hear about your MMC
I went through a similar situation earlier this year before my current pregnancy.
I found the first few months of this pregnancy very, very difficult and even as I approach the finish line I feel on edge all the time, so I can’t promise any miracles but hopefully may be able to help a little!
I had early scans but, like you, as soon as I walked out I was worried again. So I stopped doing them - they just got me worked up for days beforehand
I tried to take one day at a time. It’s not easy, but when I found myself worrying I tried to do something to root myself in the moment, like going for a walk, knitting, etc
I also kept busy with overtime at work, making sure I had something arranged whenever I was off, etc to minimise the time I could spend worrying
I also talked about it. A lot. My hubby found this hard - he felt like I was working myself up, but for me actually vocalising my worries helped me to see that they were spinning out of control, not something I could change, etc and once it was out, I was ok for a bit
Also, stay away from google!! I didn’t and it made everything 100 times worse
But ultimately, I just had to grin and bare it. It does get easier! For me, it’s never gone away and even now I fly into panic over every little thing......I’ve lost count of how many times my midwife has had to tell me that baby not moving for 30 mins is not reduced movement!
Good luck :)