Don't forget, of course, that it may not have been sarcasm, but him (her?) genuinely checking...
If you ran short of material, or delivered it as badly as you seem to think you did (I doubt that, by the way) it would be perfectly natural to check you'd finished... many people just fade out at the end of their presentations if they're nervous and so on.
If you're anxious about things, it's easy to mis-interpret what other people say.
Of course, you might be right and your professor could have been being a pillock!
If there are a lot of presentations in your course, have you thought about getting some training in the field? Or asking your professor for help, taking the initiative?
S