I am 18, I have been on birth control pills since march. in june I switched to one with lower estrogen as I was having bad headaches and nausea. I had sex about a week ago and my period was suppose to start 5 days after. last month I was 2 days late and this month I was 2 days late. When my period started this month it was red the first morning and then became brown with a little bit of dark red which I assume is because my period was late and this is it shedding the old lining (this was yesterday), and today I didn't bleed at all until later this afternoon I had a light pink color discharge which I'm not sure if it is spotting or not. I'm not sure if this is just my body reacting to the newer birth control I'm on or if this is implantation bleeding. The color looks like watered down blood. Light pink but I feel like it still looks like blood. I have been feeling a little hot and a little nauseous which isn't very abnormal for me on my period. Last month my period only lasted 5 days meaning my cycles may be shorter. I took a pregnancy test this morning but it was negative. Please tell me why my bleeding might be like this, am I pregnant and its too early to tell or are these most likely side effects from the birth control? I have had to pee what seems like a lot today but I read that if I was pregnant, symptoms wouldn't show this early. Please help.