Failed #3 ivf

I’m loosing hope here… ivf was our last hope and I really thought this would work for us.

My husband has low sperm and I was fine until we had our #1 ivf that ended up in an ectopic pregnancy and they took my tube. They said it didn’t matter since the tube wasn’t needed with ivf anyway. So all though we were sad, we were still hopeful. But now I got the beginning of my period-spotting- at 5 days past FET and I just don’t know what is wrong. They said the blastocyst was absolutely beautiful and it had hatched a bit so the timing was perfect. My uterus look nice and thick so wtf went wrong? Such a hard process and the practicality of getting off work for appointments stresses me so much since I don’t want to tell my boss because he can’t keep secrets and tells everyone. Sorry for my lack of optimism but what is going on? Why doesn’t it work?