Positive OPK in the mornings but negative later in day, plus AF! I'm super confused.

[SAHM8306]

I'm using Clearblue Easy digital ovulation predictors. I stopped birth control last month (April 24) but stopped mid pack. I missed a few pills (April 17, 18 & 21) prior to actually stopping my birth control completely and had some withdrawal bleeding that was very similar to my period. I had no bleeding after stopping my birth control on the 24th. I could have sworn I ovulated May 10 bc I had a lot of egg white type cervical mucus. I started using the clearblue easy digital ovulation predictors on May 13. On May 23rd I had positive (smiley face) at 4:30am. However later that day I noticed a brown colored cervical mucus so I did another ovulation test at 4:30pm and it was negative. The brown CM continued that night. The next morning (May 24) around 4:30am I did another ovulation test and it was POSITIVE again BUT I also had my period. A red/bright red flow plus lower back pain and a bit of cramping. Out of curiosity I took another test at 8:30am (I didn't drink anything or use bathroom in-between) and it was negative again. Why am I getting positives with first tests in the mornings but negatives later in the day? And why am I getting positives when I have my period?!? I'm so confused! Can you ovulate when you are on your period? Especially on Day 1? Can you get two false negatives like that?