Can anyone help explain to me what my BBT is doing?!

I was diagnosed with PCOS 11 years ago, but I am very atypical, I would have irregular periods, but no cysts on my ovaries, not overweight, no excess hair, insulin levels are normal, just have a slight elevation of hormones. I was on birth control to control my periods, but have been off of them for a year and a half now. Ever since I went off the pill my periods have become completely regular, a cycle of 30-32 days and my period always lasting 5 days. 

I decided to start charting my basal temp because I've heard how it has helped so many people and I don't know how much my PCOS will affect me ttc, and figured this could help me (the more info the better, right?!)

I was charting for two months and all looked normal, I saw my temp drop during my fertile week, and saw the clear rise when I ovulated, and saw my temp stay high until my period. Last month was very unusual, my temps looked normal, maybe even had a third spike in temp, and at 12dpo I started spotting, which was still around the time AF would come, but it only lasted 3 days, zero cramping, spotting the one day, and then a very light period compared to my normal periods. From what I read it sounded like possible implantation bleeding. I took a test and it was BFN, and even tested a week later and it was still BFN. Told my doctor all this and he didn't even ask questions, just said he can give me fertility pills when I'm ready. 

Since this odd period I've been continuing to chart, but my temps are all over the place! It almost looks like I didn't even ovulate! I have yet to spike in temp and I'm slightly freaking out because my husband and I are really ttc. Only thing I'm doing different this month is taking prenatal vitamins. Has anyone ever seen this or have had this happen to them??