OPK positive?

Viviana
So we just started TTC, I was on the Mirena until end of Jan, then start the pill til i had my surgery mid Feb17. Got AF on 19Mar...<a href="https://play.google.com/store/apps/details?id=com.glow.android">Glow app</a> said i would ovulate 1APR, i took OPK test and all showed neg. Then 7APR i took the test and got the results on top. one the 7th then the next day.  Im so confused. Whats going on? Anyone been in my situation? <a href="https://play.google.com/store/apps/details?id=com.glow.android">Glow app</a> says AF will now be due 23APR.