I have been on the same birth control for about 4 years. About a month ago I started having sex with my new boyfriend and during that time I may have missed two pills but I made it up by taking two the next day. I had my period two weeks ago but it only lasted 3 days (mine usually last 5 at the least) I did have sex the day before I started my period and i was not on the pill. I have been having dizzy spells, headaches, backaches, cramping and now for the last 3 days I have had a light brown discharge.. I took two pregnancy test and they both came up negative. Any advice, thoughts????