Keep taking Ovulation tests?

Laura
My last period started on January 15, and I went off/ran out of BC right after. I haven't had AF and I'm at CD 50 right now. 
My OB/GYN recommended that I start testing to see if I'm ovulating or not. I got a low fertility/negative result the other day. 
Should I keep testing for a positive or wait until AF kicks in? All this waiting is making me so anxious!