Hi Am 23,i Have Abdominal Cramps,which Is Usually Severe 2nights

Hi am 23,i have abdominal cramps,which is usually severe 2nights ago,but not last nite,have headaches,sore nipple and lower back pain,went for an ultrasound yesterday and was told I have a little fluid in my pouch of douglas,and when I did pregnancy home test today,it was positive,but am confuse if pregnancy can coincide with the fluid since its very small,i knw I and my man ain't ready for a baby now since we are plannin marriage in december,n we used withdrawal methods,pls I need ur help....thanks