Lower abdominal discomfort :( plz help...?

For the last couple of days i have had bloating and yesterday its started hurting in the pelvic region. I can feel something in there is swollen, and when i walked around the block today (like I normally do) i could feel something sort of like bouncing around in there. I feel kind of nauseous although i havent vomited. Im 19 years old and definately not pregnant (just had my period). I had a headache for most of yesterday, but i thought it might have been related to the fact that i had the swine flu vaccine yesterday morning. The pain is pretty bad and im trying to take my mind off it. I keep trying to use the bathroom because thats sort of what it feels like but even when i do it there is still no relief. Will mylanta help me until i can go to the doc in the morning??