Being that it's a film camera it takes dust on your sensor out of the question. If this is an SLR and you've been swapping out lenses maybe you got something on the rear of the lens. If that were the case the drops would be in the same locations from print to print. But the spots look to big for that explanation. More likely their processor had a bad day. Run off another roll and try again. I know that's not cost effective. Before you load the film check the seals and film bay for anything suspicious.