PCOS, Trying To Conceive, Had Positive Hpt Following Spotting. Later Negative Blood Test, Bleeding. Any Thoughts?

Hi, I am a 30 year old with PCOS . I do have one daughter who is 4 years old and she was a wondrerful surprise as it can be hard to track my cycles. My periods have been mostly regular for the past 8 months while taking Metformin and losing 30 lbs. I have been ttc this entire time, using an ovulation predictor kit and timing intercorse during my positive ovulation/sticky mucus days. I think I had one very early miscarriage during this time and going through something odd at the moment. Last Friday I started having very light spotting with dark brown blood, with light cramping. (Not enough to need a liner or tampon ) This lasted through Tuesday.However, on Sunday I was curious that this could be implantation bleeding since we ttc during my fertile time12-14 days before. I took a at home urine pregnancy test, it came back positive. The next day, Tuesday, I went into my Dr s office to have a blood pregnancy test done. It came back same day negative with a HCG quant. 2. I know it should have been at least 30-1000 by this time. So my Dr advised I come back in on Friday and have another blood test done. I did so and it also came back negative for pregnancy. ( 2) So here I am thinking that was a chemical pregnancy or a evap line. Then today I used the restroom on Sunday and I am bleeding. This time more red blood and I would say it is in between spotting and regular bleeding. What are your thoughts on this?