Weird period

Okay, so my entire life I've been regular but in December I was 2 weeks late, and then this month I was 2 weeks late again. And it could be from stress, but I've also always had a really painful and heavy period, but they've been short, not painful, and light. I know it's something I shouldn't be worried about, but I am xD any advice? 
Also I'm 20 and a full time student.