You are on birth control. Birth control is 99% effective. You are not ovulating. Therefore, you are not pregnant.

If you don't have your period, take a pregnancy test. If you do have your period, relax.

some women expierience bleeding during the first trimester or even during their whole pregnancy

but its usually light pink or brown blood not bright red

If you're on the pill AND getting your periods, there is no reason to think you are pregnant unless you have been really bad taking your pills.

What makes you think you could be?

A missed period is the first (and most reliable) sign of pregnancy.