I haven't had my period for a long time.?

Weight does play a role in your periods, I have had that issue since I was a teen myself and to this date still am very irregular! I myself go for months too without. Get your thyroid checked, watch your weight, eat healthy and talk to your doctor about it.. sometimes over exercising will delay it as well. And yes if you don't have a period every month getting pregnant can be much more difficult since you don't really know when you are ovulating!