I keep falling asleep at the worst times
Why do you think you are falling asleep like that?
I think I must have an over-sensitive deep sleep switch in my head.
If you fall asleep at inappropriate times, you should either work on setting a good sleep schedule for yourself, or get checked by a doctor. A doctor can help you figure out your sleeping problems.
I'm fine. It happens rarely.
If you are truly fine with it then okay. It's still good to get a check up at the doctor every once in awhile.