Is this normal?! I'm scared please help me!!?

So I've had my period for about a year now, and it's not regular yet. I'm 13. And the blood has been coming out in big globs. Is this normal? And it seems to be heavier when I sleep, cuz during the day it's very light. A few days ago there was two giant globs and it was all running down my leg. Please help me! Is there anything I can to slow this down or make the big globs not happen? Please help me!!! Thank u