I have a five month old son.. I am breastfeeding about three or four times daily anf on birth control.. Never got a real period after the three weeks of straight bleeding after my son was born... Am I pregnant? Can I take a pregnancy test? Help!

If you are having sex of course you could be. It could be many things, have you discussed this with your doctor on some return check ups

It would be possible, but unlikely. The birth control would be one barrier, and for many women breastfeeding will be another... although neither are 100% effective.
Exclusive breastfeeding works best at preventing pregnancy, but some women will find even some regular nursing sessions still does the trick... best not to rely on it however.

It is not unsual to not have periods return until you wean baby. Some women will have a return just from the number of feedings being reduced... some not until you stop altogther or reduce the number substantially.