Missed miscarriage 💔😭

I found out Thursday my babies heart had stopped a few weeks ago and was measuring 8w4d when it had a strong heartbeat at my 8 week check up. I joined a group on Facebook and just keep wondering why did it happened. I happen to read a comment about bending alot could cause this. How true is this? I'm a sahm and I was bending over constantly since I have a toddler and doing house chores. I just need closure why it happened 😭 I was also under ALOT of stress and kept thinking why did I get pregnant since it was unplanned and now I wish I could take those words back 😭