Period was last week, lasted about as long as it usually does but lighter. had awful mood swings, not wanting to eat, and constantly tired. pregnant?

Can do a preg. test: It can be hard to tell if a woman is pregnant because some of the symptoms seen in early pregnancy can also happen in non-pregnant women. A urine pregnancy test gives a reliable result if done correctly. One can test 3 weeks after sex (when conception might have occurred) or 1 week after starting a "weird" period. An Ob-Gyn doctor can evaluate if there are any persistent or worrisome symptoms.