Hi K, Well stress will do that, and just genral worrys will upset our bodys.
Good Luck
Well I think I must have just been stressed last month. Because it came around the time it normally should. Who knows!
Hi K, what was it before, or has this been slowly getting longer?
Do you mean your cycle has been coming every 37 days? Everyone is different so for you this may be normal. Many women go their whole lives with mildly irregular periods. Things such as hormones, stress, anxiety, etc throw it off at times so sometimes it will come later. When things are a bit more balanced, it starts getting back on track and will come a little earlier than before. It's pretty normal. I'm 25 and it's still like that for me.
If it worries you, it never hurts to go to the doctor for peace of mind. Not to mention at the age of 20 you should already be seeing a gynecologist yearly for PAP smears and pelvic exams. They could address these concerns best.
Good luck =)