Stress and anxiety can be linked to odd cycles. I am remembering that when I first got together with my husband, I was on birth control but had a 6 week long cycle. No apparent reason all negative tests. I was maybe 20-23 years old at the time. I have had two other strange cycles as well. One when I was 14 due to a cyst on my ovary. It burst and I had to go to the doc. I had a 3 week long menstrual cycle and had some pretty good cramps going. I have had cycles on birth control where I had month long periods with no reason and a few months ago I had a random 9 day long period. When I went to my local public health department for my annual exam, they told me it could be a fluke or an early miscarriage even without a positive test, so I don't know. I think your best bet is to call your county public health department and see if they offer papsmears and such. That may help. Another option is to again wait 3-5 days and see. I have never been pregnant, so I don't know the difference, but I don't know if its supper common to have painful cramping in early pregnancy. Either way you should get checked out in case its an etopic pregnancy or something.....