Wat are the misscarige symptoms ?

May be none: Depends upon the stage of pregnancy and the cause of the miscarriage. Often there may be vaginal discharge, cramping, alterations of symptoms of early pregnancy, etc.

Heavy menses: Usually feels like a heavy, extra bloody period with lots of cramping. If you don't stop bleeding or cramping after a few days, get an ultrasound to check for retained products of conception. And unless you are intentionally trying to get pregnant make sure you are using birth control or have quick access to Plan B (it's otc now). You are very fertile at your age.