If you actually did get water in your lungs, he's right, TBC. You need to get checked by a doc if that's the case.
Most time when you get water in your throat, your windpipe closes over and even though you cough and gag you don't get water in your lungs. But if you are drugged, or even heavily fatigued, this may not happen fast enough to stop water getting in your lungs.
Play it safe - see a doc!
Cheers
Mick