Bright red blood, shouldn't be period

[Equiem89]

I'm 27 and have been on the pill since 17. Was on Yasmin since about 20 and last year I got changed to Lucette which I've been taking for about 5 months.
For the past year or so I've had brown discharge for the last week of my pack of pills, I mentioned it to the nurse on my pill check and she said its fine. I wasn't too worried it was just a bit of a nuisance. However after another thread where the OP got a referral under a two week rule I've got a bit worried so I booked a GP appointment, I phoned on Tuesday and the earliest I could get is next Monday with the nurse practitioner.
I'm on my last week of pills, break meant to start next Tuesday.
I woke up this morning, went for a wee, when I wiped there was loads of bright red, obviously fresh blood. I'm really scared. I've never had this.
I have cystic ovaries, that was found on an ultrasound when I was being tested for endometriosis, which I don't have.
I know I've got my appointment on Monday but I'm now really worrying that something is really wrong. I bleed every now and again after sex, not all the time.
I've been feeling heavy in my lower abdomen for about a week or two, maybe a bit crampy but I do have sight IBS so put it down to that.