Hi!
Has anyone experienced their lenses popping out

I was at a tutorial the other day and I got the feeling my eye was rapidly drying out, suddenly and with no warning my lens popped out of my eye

. Luckily my glasses stopped it shooting forward and it fell down onto my lap

It was a really strange sensation. I think the air conditioning was on in the room at the time and can only put it down to that. However, I am a bit concerned that if it happens again I might be upright and then I will lose my lens

.
My lens is a soft one - one of the new types. It is really comfortable most of the time but every so often it seems to suck all the moisture out of my eye and the only thing I can do is remove it re-moisten with lens cleaner and re-insert it! Is this usual
As you can probably tell I am fairly new to lenses and so any advise would be useful please.
Sally