What happened?

I'm in my 2nd month ttc and I've been using Glow and recently Fertility Friend (I like the charts as they are clearer) to try and predict my cycles. I thought I'd recently ovulated due to positive opks, fertile cm and cervical position but today when I took my temp after observing what I thought was a shift in temp, it's suddenly dropped back down. So what happened? Did I not ovulate? I did get out of bed 30mins before but got back in, could this be why my temp doesn't match? Thank you in advance.