About a month ago, I found a large protrusion quite a ways back inside my vagina that I don't think was there before. I wasn't sure if it was a bartholin cyst because it was farther back and in the middle, not the sides where the glands are. It is painless but quite large and protruding. How do I know if it isn't just my cervix as I don't know how far the cervix is supposed to protrude. Could it be a cyst or just my cervix?