I'm 17 I've had my period for years but this is the first one where I've tried tampons. It feels uncomfortable in me and I can't tell if it's the tampon that hurts or just cramps

Also, yesterday it was in for about 4 hours and all of a sudden I started leaking this clear fluid with a little bit of blood in it (it was mixed with blood but it definitely was not blood it was a liquid) and when I pulled the tampon out it wasn't even close to being full yet, I'm just not sure how a tampons supposed to feel or anything. It doesn't hurt to put it or cause major pain or anything, do you have any advice?