help?!

Hey guys! , so for the last two weeks I've been having to wear tampons , but it's not my period . If I don't have a tampon in I'll have a tiny tiny bit of like watery blood . But when I have one in there will be quite of " unusual " looking blood that has a bit of a funny smell. After I take the tampon out I sting a little. I've also not had a period since December .. anyone got any advice on what it could be ??