Help... Im confused.

When I woke up this morning and went to the bathroom i wiped and i had blood as if i was on my period (but i don't start for 6 or 7 days) so I just put a pad on and continued with my day i went to cheer practice and then ate lunch and then i went pee when i went pee this time and wiped there was brown blood on the toilet paper i am on birth control and this up coming period will be my first one with this birth control but what could be the problem?