What To Do For Irregular Periods?

Hello since i gave birth to my first child i've been having problems with my menstrual cycle my problem consist on having my period for two month and then it stops for two weeks and then it come right back. My son is two but lately i've been feeling lots of movement in my abdomen. what can that be. i have'nt been to the gynecologist because i'm scared, i'm only 23 years old. Im overweight and i dont know if thats also causing my problem, and i dont know if what i feel inside is that i could be pregnant, i dont take any birth control. Please let me know. I usually feel the movements at night or when i eat, but right now i have my period and im bleeding a lot.