Discharge problem!! please HELP!?

So whenever I'm soon to get my period, I get really heavy discharge. I normally have very light discharge, but now its really heavy that it sometimes leaks through my trousers/shorts/skirts. And I suffer from thrust every now and then and its quite painful. I'm like 13 and I've been on my period for almost 3 years. Any remedies to reduce the pain from thrush and reduce the heaviness of discharge. Appreciated for help.