Hi! It definitely is possible for stress to affect your cycles and with your schedule, it sounds like you qualify for stress! I would suggest seeing your doctor--he or she could double check the pregnancy test and then in a case like yours, I would give progesterone to start your period. (presuming the test is negative.) I like to use natural progesterone (Prometrium) because if you were pregnant and the tests were all wrong, it would do no harm at all to the pregnancy. If you are not pregnant it will start your cycle and help to get rid of all those "PMS-y" feelings. I will often give my patients a couple of refills just in case it happens again--other doctors may not want to do that.
Also, if it happens a lot--you might want to consider cycle control with oral contraceptives--you also get the added contraceptive benefit.
Good luck!
Dr B
6 weeks ago I took a preganancy test after feeling the samy symptoms and they were all negative but took another one five days ago it was positive. get blood test done