I am on birth control and I am cramping in my lower abdomen... and I am bleeding it is light pink and only lasts for a few minutes... I was wondering if that is a sign of pregnancy

That is a sign of pregnancy.

It is always a sign of a dozen other things also.
No form of birth control is 100 percent effective

You'll have to wait at least 2 weeks after your period is due, then test using first morning urine.

If you're due for your period, and you're only spotting, it could be anything. It could be that you're having an off month, it could be that you're pregnant, it could be an STD, it could be an injury, and so many other things.

We can't diagnose pregnancy online. It's up to you to determine if you're pregnant or not.

Good luck.