Positive OPK 's but BBT is Low.. please help

This is my first time using opks. I got a pos opk on cycle days 10-14 and my temps dropped from 97.3 to 96.9 on CD13. CD14 went up to 97.20 but then dropped down to 97.10 today CD15. Aren't temps supposed to go up and stay there? Is it normal for my temp to be low after ovulation?

The second half of your cycle should have higher temperatures on average then the first half of your cycle.  Sometimes, though, it takes a couple days after O for them to get back up.

Maybe I'm not ovulating this month since I just got off the pill?