Anyone have problems getting pregnant or having a period after ONE depo shot?

I bled for 3 months while on the shot, to stop bleeding my ob gave me BC pills and i only took them for a month. I had a regular period Sept 10 and nothing since, i took a pregnancy test in the end of October and it was negative. My breast are bigger and i have gained 2lbs this past week. Should i have my dr administer a pregnancy test? Or is this the Depo shot haunting me?