Talk to Gynecologist on Movement During Pregnancy

i hv 24 weeks pregnncy .. sometime i feel much something in my belly but some dys there is no nothing at all ...i also consult with my doctor she just says its not babies movement its only gas.. movemnt will b in the next month ...but i dont feel even this gas now from 3 4 dys wt can i do? is babies movement stop r wt is this kindly help its my first pregnncy i hv no idea