if you were you would get a positive hpt,
It's most likely due to the hormone changes of going off birth control, and pretty unlikely you're pregnant. Generally, red blood in pregnancy, isn't good anyway, especially early pregnancy, so if you were pregnant it would need to be seen asap. I noticed you posted this in the teen pregnancy forum a few days ago, and unfortunately unless it's a concern, there's not much we can do in the way of help! Good luck!