Could I be pregnant? Or is this just my bodys response from withdrawl of BC?

I took birthcontrol for a month (sprintec) during the first two weeks i took the pills at different times until i found a time I could stick to and during those two weeks I was sexually active. During the placebo week I had spotting once a day, for two days then had what may have been a light period for less then twenty four hours. I stopped taking the pills after the placebo week and every night i get extremely nauseous. Two weeks later, I have been feeling pressure in my lower abdomen, have had a few muscle spasms close to my belly button and so far today, I have been having occasional light bleeding and a light brown discharge and I am very fatigue and breasts are a little tender. I have also been a little gassy. Could this be from stopping the pills after only a month?