What is happening??

Me and Hubby are TTC, we were very sexually active during predicted fertile window this month (i don't use ovulation strips but just purchased some, but I've always been able to feel my ovulation). I'm 4 days late and all tests are negative! Not even a faint line. I'm cramping here and there but my cycle is always like clockwork. What do i do? Wait a few days? Wouldn't i have a positive by now?

I'm extremely frustrated because I have no idea what would've caused me to not ovulate this month if that is the case.

I have started dieting the past 2 months (not snacking after 8pm, still getting my calories in though so not restricting myself) but I've only lost a couple pounds. Would this cause a big change in hormones? I don't feel like I've been doing anything drastic at all.