Need advice

I need advice. First of all, I got my IUD removed on Oct. 18. My periods never went away and I still ovulated most of the time. My Ob/gyn told me that my cycle shouldn’t be affected because my periods never went away while I had the IUD. My husband and I wanted to start trying for another baby, so I purchased some of the cheapie Amazon opk/pregnancy test strips. I took one on the 18th for fun and it came back very positive. My husband and I had sex everyday day that week and the next. My apps said that my period was due Oct 23-25, but hasn’t shown. I have irregular cycles, so I’m not surprised. If I ovulated on the 18th, my period should have been due yesterday, but I still haven’t had any symptoms that I normally have with my period (spotting, back ache, severe cramps, etc) but I have been nauseous and my boobs are sore. I took this test today, and I swear I see a line, but it’s hella faint. It I’m already 15 DPO, when/if should I retest? I didn’t test positive with my first until 18 DPO, but he also took me by surprise and I wasn’t looking for it.