I had unprotected sex a few times this month, my period is two weeks late, i had brown spotting,took two test both negative, could i be pregnant still?

It depends: It depends on when you did the pregnancy tests. If you waited until your period was late it is extremely unlikely that you are pregnant. Lots of things including stress can cause your periods to be late. Sounds like it's time to see your doctor to look into it and while you are there discuss a reliable method of contraception unless you are trying to conceive. Good luck.