I'm 18 and I've been on NuvaRing for a little less than 2 months....

I'm 18 and I've been on NuvaRing for a little less than 2 months. The first month was fine nothing out of the ordinary except that it kept slipping, it wouldn't stay all the way up in my vagina(and still hasn't). My doctor told me I could either do 4 weeks in and one week out or 4 weeks in and then put in another one right after(so i wouldn't have a period). I put the new ring in just over 2 weeks ago and started to experience abdominal pain(i thought it was just a pulled muscle or something), but then I started to get a brown discharge. Last week I started to feel absolutely sick to my stomach and am so tired all the time. I decided to take the ring out on Monday since the discharge hadn't stopped within a couple of days. I also did this because I had started to get terrible cramps and diarrhea. I had to skip 2 classes because they were so bad. I almost never had cramps before but these are so terrible that not even a hot shower and Ibuprofen can fix them. How long will it take for this to go away since I didn't use the ring for the entire time? I hate feeling like this, I can't really function. I'm glad I'm not alone on this.