Big Tampon problems. Please help me out!?

I've had my period for over a year and have tryed tampons last summer and just now, but when I insert the tampon it feels dry for a while. After about 10-15 minutes, it still feels dry. Then, when I sit, it feels kind of uncomfortable, not like HOLY CRAP uncomfortable, but uncomfortable enough for me to notice that it is there. Also, when I walk, it fells like it is rubbing me on the inside. I have heard that if it feels slightly uncomfortable, it is in wrong. I use regulars (tampax pearl). Is it possible that I need a lighter flow tampon? I am trying out for colorguard and have a clinic tonight, but it will be difficult for me if i have to wear a pad. Please help me!!!