Mucusy discharge, and then bleeding?

My period stopped a week ago, and just last night I started bleeding again. My period this past month was unusual, and it was short and light. Usually it lasts about five days, getting heavy on the third day. However, this past month, it never got heavy, and it only lasted about three days.

Me and my husband had sex last night and I got in the shower almost immediately after. I noticed a thick, snot-like discharge. About an hour later, I started feeling some moderate cramping (like a period, but more of a deep, almost stabbing cramping). About another hour passed, and I went to pee and noticed I'd started bleeding again.

It's been about 24 hours and it hasn't stopped. It's not a lot, and I don't think its spotting because as far as my understanding goes, spotting only lasts a few hours at the most.

I was wondering if there's a possibility it could be a ruptured cyst, or even implantation bleeding. The blood is a mix of both pinkish red and a dark chocolate brown, which doesn't look like my usual menstrual blood which is usually a dark, rich red color.

My sister was recently diagnosed with PCOS, and I figure that if she has it, there's a chance that I could too. I've always been irregular with my cycle, and I've been on the pill for about two years, which has fixed the timing irregularity for the most part. However, the duration and amount I bleed has changed over the past year.

Does this, in your opinion, warrant a trip to the doctor?

Does this sound like a cyst, or implantation, or do you even know?