I was on a different brand of birth control but i switched pharmacys so my brand switched to lutera, ive been on birth control for about 4 months and this was my first month of lutera, it was the first saturday of the pack that i missed, so i took 6 pills then missed one and took 2 the next day. I had sex on that saturday but my boyfriend pulled out. Like 3-4 days later I started experiencing brown discharge and its been going on for like 6 days and getting heavier. What could this be?