It is probably just gas. I know that before I was pregnant I used to freak myself out because I could feel a hard lump under my belly button then a few minutes later it would move to my side and I could actually see the lump move. If you are too concerned though, visit the doctor.
Hello,
If you are getting your periods, pregnancy cannot occur. Once pregnancy occurs, cessation of menses occurs. The feeling of fetal movement can be due to peristalsis movement or due to muscular contraction of the abdominal wall.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
Go see your ob/gyn and get an ultrasound. If there's a fetus inside, it will show up. Are you sure you aren't just getting gas rumbling around or something else that would cause a sensation of movement, though?