I agree if you have been feeling constant movement I would call your Dr to see what he/she thinks you should do if drinking cold drinks and laying on your side doesn't work
Were you feeling regular movements before? Try to drink a cold glass of water, or apple juice, and lay on your left side still for an hour, if he/she doesn't kick much I would definitely call your OB just to be safe, it's probably just an off day for him/her, my son would have days between 25-30 weeks where he wouldn't move at all, but better safe than sorry!!