Implantation bleeding??

I’m new to this, forgive me if TMI! My husband and I have been TTC for 3.5years and never been successful. I have PCOS which seems to be our only obstacle and have recently been referred to the fertility clinic. I started taking fertility supplements about 2 months ago. My periods are usually every 5-6 weeks, I get major cramps (I’ve been to A&E; because they’ve been that bad before), major boob ache, leg ache, mood swings, bloating... you name it, I get it. Anyway, my last period was the 9th-15th May. According to my tracker, Glow, my period isn’t due until the 12th June and I ovulated last week. We did a lot of baby making during the week, and then on Saturday I had a really light bleed. The day before I’d had egg white CM. On Saturday, It was red like a period, but so light that I didn’t need any feminine products. It was only noticeable when I wiped. I’ve had no period symptoms at all minus light cramps in my stomach on Sunday. 4 days in and I’m still bleeding ever so lightly (usually I have to change tampons every 2-3hrs and I’m in agony) but it seems to be stopping. I have NEVER had spotting before, the smallest cycle I’ve had in 13 years was 31 days. I feel really deflated that it could be my period but the fact I’m only on CD20 makes me feel like this isn’t a period and could be implantation bleeding? I’m getting no other symptoms except the occasional flutter in my stomach and the last 2 nights I’ve had major insomnia and slept about 4 hours. Today I am shattered but I’m putting that down to lack of sleep at a 6am start at work, but is it possible this is implantation bleeding??? When should I test???