[rr21]

i have no idea what happend to my car but im thinking its the battery. My car is 06 325 i e90 and i parked the car in a parkinglot, turned off the car as i normally would and pulled out the key. after pulling out the key i hit the start/on button and pushed it again thinking the car was off...2 hours later after i finished my class i saw that my head lights were on. when i tried starting the car the panel lights flashed but it didnt start...i tried couple times....anyone know what the problem could be and what i could do...the car was not started because i had taken out the key...im thinking its the battery but the inside of the car the lights were working.