Is it the stress?

Hi everyone! My cycle usually lasts around 36-37 days but it's now about 3 days late. I have had an irregular period in the past few years, but since Jan. this year, it's been very regular. It's almost the end of the semester at Uni, so I've been dealing with a lot of assignments that need finishing. My question is, would it be possible thats it's stress that's causing my late period? How easy is it to be thrown off your cycle from things like stress and weather changes?