Menstrual cups?

So I've recently starting using a menstrual cup, I really love the idea of using something so low maintenance, pads break me out in rashes and tampons make me feel funny. While i love everything about the cup, I'm having some issues. I'm not sure if it's just because its new or if it's not right for me. Im using a diva cup, i think its medium one. I am a virgin so i know thats a factor in it being so uncomfortable for me. I just wanted to ask if anyone else has had the same troubles. Ive gotten the hang of inserting it, but when it pops open it hurts for a good 10-15 minutes after, i dont know if thats because im not used to it or it's just not open right, ive gone around the brim of it and it feels open, it doesnt leak. Is it just something i have to get used to? Also, i cut the stem off because it was uncomfortable, but even without it its still poking me and i have it flush with my vagina, it also feels like it may come out when i pee and i can see it moving out some. I'm just not sure what to do and i cant find much more online, any advice?