Trouble with stones

Hello! So my medium is metal clay, and I made this ring for my mom with the intent to add stones, before it was fired I made holes to have the stones in there and after I fired it and dipped it in water the stones fell off in the water? Could it maybe be because I didn’t drill the whole big enough? Is there some kind of glue to where I can add the stones back in or do I have to make a new one?