Birth Control ruining my body

I’m 17 & I have had acne for most of my life, pretty regular and normal periods, and have just started having intercourse. I decided to start birth control pills and it went very wrong. I took the first pills I got for 3 days at 9:30 before bed. I woke up each morning with a burning headache and extremely nauseous to the point where I would actually throw up. I finally decided to stop taking them and the 4 the day I wasn’t experiencing these symptoms. After stopping them, I’m almost positive that it gave me a yeast infection & I have had more and different discharge than I ever have. I didn’t want to stop trying, so I got on a different form of pill. The same thing happened again after taking it for 2 days, but worse. I stopped them all together and went back to “normal.” After a bit I started lightly bleeding for a couple days and then it stopped. I was nervous that I was pregnant, and still am, but I have no idea if it’s just messing me up or if this is not related. About two weeks later I started lightly bleeding again, but this time with mild cramps, which I usually never get. What should I do?? I can’t tell if this is the birth control causing spotting the first time & now this is my period but a lighter version due to the hormones even though I stopped taking it. I was suppose to start 2 days ago, so it would fit, but the lightness is confusing me.