I had unprotected sex six weeks ago but we used the withdrawal method. Have been on birth control since April but have been switching between to find which works best. April to June was on minastrin, July and August was on yaz and just started Sprintec in September. Started with back pain the week before I was get my period, started spotting and had a light period. Took a home pregnancy test which was negative. Four days after starting Sprintec I have been having abdominal pain to the point I don t want to eat, occasionally feeling nauseous, burping and feeling gassy. Is this just from the new birth control?