CD21 - Break cycle turned natural cycle

Today was my follow up RE appointment. Had my blood taken by my not usual nurse who kinda hurts, and then went to get my ultrasound. My 16mm (on Friday) follie is now at 15mm, oddly shaped and has liquid around it. The tech said I am in process of O'ing. She was very happy. My lining was 10mm on Friday and is now 11.7mm, it’s thick, but the bleeding is just spotting now. They then asked if I completed my homework that was assigned to me (relations with DH on Monday), of course I did on Friday, Sunday AND Monday!~! So they next did a PCT (post coital test). We waited to be called back to speak to the RE. What he said is that 1 of 2 things can be happening. 1- I am ovulating on my own which is great or 2- it’s a fake out…a follicle that is empty. The nurse will call me with the results of my blood work. If #1 is true than we had good timing with our relations and the doctor said my PCT was good (last time I had dead spermies). If #2 is true, he gave me a prescription for provera to shed the lining. Once I shed that lining, we will start with clomid and follistim. I asked what could explain the bleeding, he said hormone imbalance. I asked if the ovulation that I may be doing is a residual effect from the oral meds I have been taking, he said no, that my body is most likely metabolizing correctly due to the Fortamet.