This is new to me. CP

So I believe I just experienced my first chemical. I tested on the 3rd, one day before AF was due. I don't track ovulation because my cycle is always different, I have pcos. Well the test on the third was positive but faint. I tested again the 4th and 5th and had a blood test. All negative. Today AF shows up. There were small clots in the toilet and I'm having a heavier flow with severe cramping. I was just wondering how fertility and ovulation work after a CP.