will they just get heavier?

I'm 14 turning 15 in May. I started my period when I was 12 and I'm very irregular. My period sometimes skips a whole summer. And it's very painful and heavy and ovarian cancer runs in my family.. I'm not sure if it's genetic but could I be developing it. And when I say painful I mean I have to stay in bed curled up in a fetal position. Why is it doing this so early?