I recently had a real short and light period I am on birth control and it has never happened before been on it for 1 year could this mean I am pregnant

Pregnancy is possible. Pregnancy is always possible if you're sexually active, with or without birth control.

You could also be having an off month.

Only way to know is to try a pregnancy test. If it's negative, wait a few weeks and test again, or see your doctor for a blood test.

No way for anyone to diagnose pregnancy online.

Good luck.