minipill, weird periods, anyone else?

F

Ok so a little backstory, I was put on a normal combined pill at 17 after trying other non hormonal medications to help with severe period cramps and very heavy periods. I took this for a couple years then stopped for 3 months because of a possible link to migraines and I then went on to a minipill (noriday). I'm now 21 and have taken that for around 2 years I think and it stopped me having periods. Then last November I had one randomly, I had one in January and then in March I had a 2 week period and then 8 days off before it started again. The cramps are painful enough to make me cry, I have constant nausea to the point I'm having to take travel sickness pills and I feel awful. I'm bleeding way lighter, but it's all black/brown no red new blood at all. I've got a doctor's appointment but I was looking for some reassurance that I'm not going crazy because I'm losing it right now!