What Causes Irregular Periods After Starting Birth Control Pills?

cycle problems started a birth control in march, it caused a lot of side effects, tried to ride it out and adjust, but it came may 19th and i stopped after 12 pills. may 1-9th i had light spotting, nothing when i went to the bathroom, only in between. went to doc and gave me some pills to get it to stop. May 13th white thick discharge threw the 16th may 19th stopped birth control. night of may 25th light spotting red/brownish color lasted til morning of 28th. morning of 28th turned into a dark brown pasty looking discharge, then nothing after that, probably could have used a panty liner the entire time with how light it was. had slight cramping, thought period was going to start early (due for af the 31st or 1st of june. it s always either a sat or sunday) today june 1st had little white discharge milky/clear. been feeling like period is coming all week on and off, but still nothing. Took hpt friday, negative. lots of headaches, usually i only get one the day after af comes, very tired. had a pregnacy 7 years ago, didn t have any symtoms the entire pregnancy. so i m not sure if i am or not. intimate on may 8/9/10/11/13/18/20/25/28/29/30/31 no condoms, but he pulls out, which i know isn t the safest.