Depends on the shape, size, the amount, and what else you have in your stomach.
Glass can't be digested, so your body will try to pass it through in whatever shape and size it was when you swallowed it.
Something like a glass bead will be entirely harmless, while something like a bigger shard will mean serious injury and possibly even death.
And of course everything inbetween depending on shape, size and whether it gets embedded in other stomach contents or not.
You Die
you die
you die...
pain
Nothing happens
You can get chemical burns along your throat and stomach if you swallow lye.
You burp bubbles
Good question, just today I've found a bit of broken glass in my food (Indian restaraunt in London), but I've realised that before swallowing. Quite a good answer is there - http://www.corecharity.org.UK/The-Hazards-of-Swallowing-Glass.HTML.
It depends on how much you swallow. If it is a large amount, you could get diarrhea and/or vomit.
Mold grows in your tummy
This too will pass.
go ro the hospital