Had protected sex, period 2 days after and lasted for 6 days. Haven't had for 3 months, could I be pregnant ?

Are you normally very regular with your periods? Have you tried a pregnancy test? Could be irregular cycles, for a number of possible reasons, but certainly you'll want to test for pregnancy. Best to see your doctor so that they can try to determine the cause for a lack of periods.

If you were having sex, of course.

If you have missed three months, what is the results of the pregnancy tests