That sounds like a LOT to process, mamak. I'm so sorry to hear about your MIL - my FWH lost his mother exactly 5 years ago and we're still trying to process it sometimes.
It's ok to have doubts. It's not fun, but I don't want you to start beating yourself up for trying to move.
We moved too, and even though it's away from where COW lives, it's close to where some of her family lives. (thank you fb ) That bothered me at first, but the likelihood of running into her is so miniscule that I don't ever think about it anymore.
I remember, about 5 months into the move, I started to really doubt everything. It was a fresh start, but we brought a lot of our stress with us, and moving with kids and pets and everything is really a stress trigger in itself. You'll argue more, you'll feel exhausted a lot of the time... it really takes a while for the dust to settle.
You've been dealt a lot of challenges. Try to take things in small steps for a while. Don't worry about the big picture, just try to be where you are and be ok. It doesn't have to be perfect, and it doesn't have to be permanent. You just need the merry-go-round of life events to slow a bit so you can see where you are.