My last period was 10/15 i haven't had a period this month but all of a sudden my back hurts, i have headaches, and my stomach is tight! am i pregnan?

Dysmenorrhea vs preg: You could be close to your next period and your symptoms may be part of the premenstrual symptoms. Wait a few/several more days- you may have your period started. Sometimes, depending on your pattern, period can be a bit earlier or a few days delayed-and is still normal. But if you are worried about getting pregnant- buy the pregnancy kit and check it if you still dont have period over the expected.