Ugh to the unknown

Seriously am so confused by the female body. Hubby and I decided in January to start TTC. Had AF in January around the 23rd. Used Clearblue Ovulation to get a gage of when I ovulate because I’ve been on BC and never tracked that before. I was supposed to get AF 10 days ago. I’ve been feeling off the past two weeks and have taken a few at home pregnancy tests but all are coming back negative. If AF isn’t here tomorrow I think I’m going to call the doctor and try and get an appointment seeing as though Monday would make me 2 weeks late. Just not sure what’s causing it to be late if the tests are all negative.