Is this normal?

I'm 15 and ever since I've gotten my period (age 11 or 12) I've had discharge all the time! Every day I feel like I've wet myself cuz my underwear is soaked. It's awful. Sometimes it's sticky, sometimes it's watery. Sometimes it smells a little but I can't tell a difference between it smelling and not smelling. I am just worried that it's some big disease or something. So is this normal?