My husband and I have been TTC since the end of February. I started using OPKs this month in the hopes that we would get pregnant...well on days 14 and 15 of my cycle I got positive OPKs. Day 16 and 17 negative and now day 18 I get another positive. What does this mean?? I am so confused? I took all of these tests between 4 am and 6am.