Need advice on irregular periods and OBGYN appointment

Hi, I'm Rubie, new on here and hoping maybe some people can help calm my nerves about my situation? I started having irregular periods a couple years ago to the point that I was unable to move for days out of the month. I talked to my doctor and was put on the pill which made them very few and far between at first, but now I'm not bleeding at all. I thought it was normal but apparently it's not because my GP is very concerned and I have an appointment with the OBGYN soon. I'm incredibly nervous because I don't know what to expect or if I'll find out something is seriously wrong. I'm also scared they'll take me off my medicine and I'll be stuck in horrible pain again. Any advice/words of reassurance?