Have you been to the vet yet? ANy updates?
Fingers & paws are crossed here.

I think she probably just had a lot of gas, which can cause the stomach to bloat. She probably just got into something when you were not looking, or someone gave her too much or just the "wrong" treats or table scraps that didn't agree with her stomach.

Granted it is good that you were so serious & concerned as bloat is a very serious illness & should be monitored very closely, and of course the symptom of a bloated stomach is one of the signs of bloat.