Medium Sized Blood Cloths During Period At Age 13yrs Old?

Im On My Second Period.It Started On The 15th Of June.Yesterday I Had Small Blood Cloths.Today When I Changed My Pad They Were Medium Sized..Later When I Had It On..It Felt Like They Were Getting Bigger!! It felt so uncomfortable because it felt like gushy of fat were moving through my...eh Em.Is this normal? And Also i don't know if cramps are starting to come or something but where my eh Em area is (lol) it feels...heavy..like there's a lot of weight right there..whats wrong? ihaven'tt been drinking water much.will water help or would that make my period worse?