I took birthcontrol for only 3days on my last period. my period was due 6 days ago, and hasn't came yet. but i was cramping as normal. could i be preg?

Periods: A simple otc pregnancy test should provide the answer.

Of course: Taking 3 birth control pills early in a cycle is not effective contraception, might delay the next period by a day or two. You say your period was "due", meaning you are usually quite regular? Being late in someone who is so regular is always a concern for pregnancy. If you are not wanting to be pregnant, you need to practice reliable birth control, as you have decided to be sexually active.