Urgent

The past couple days I have been cramping in my lower left abdomen and lower left back, I also have been very nausious, iv have discovered this morning that There is a little lump where the pain is in my abdomen and my stomache seems to be bloated often. For the last few months i have also had irregular periods, getting a period every 2 and a half weekes or so. I really want to know what this could be. It is very uncomfortable and gets pretty painful. Please help.