My last period ended on april 13, and then after 22 days I had another period that last for 7 days (may 5- may 12) its…

My last period ended on april 13, and then after 22 days I had another period that last for 7 days (may 5- may 12) its dark brown and painless no feeling of pms then I had a light period (the blood just came out one time and is dark) today May 29 after I felt period like pressure under my belly but after I ate nothing followed. What can be the cause, am I preggy?