What if you had sex and two weeks later your period came on and didn't go off until 4 moths later... reason being because i think im pregnant.

Ask a clinic or a doctor... there is no better advice you will get on an online forum than that. You actually bled for four months straight and didn't call a doctor?

If you think you might be pregnant, try a home pregnancy test, or see your doctor about having a blood test done.

It is not normal to bleed for four months straight, whether you were pregnant or not. There are a number of possible reasons for continuous bleeding... pregnancy would not usually be one of them.

Being pregnant does not cause you to have a 4 month long period, if that is what you are asking. If you have had that, you need to see a medical professional

I agree with all of the above, pregnant or not you should not have a 4 month pregnant and should see a doctor to have some investigation done into why you are bleeding so much.