Suggest Treatment For Irregular Periods Along With Strange Abdominal Movements

I am a 26 year old mother of a 7 year old and 3 year old. Never had a miscarriage but always have had problems with my cycle. A few months ago I took a pregnancy test at home and it was positive but went to a clinic and took one and it was negative. My cycle has been very odd and I have been feeling movements in my stomach area. What could be wrong with me?