Erm, I wouldn't be embarrassed about this. You know your bunnies well and gut instinct is very important.
To my knowledge, none of my bunnies have ever been 'full' and never, ever refuse a tasty morsel, so I think you have a right to be concerned. I would also argue that tummy troubles can come and go very quickly in bunnies.
By all means leave it a while before ringing the vet back, but I would be taking proactive action too. In my case, I would syringe a little cooled, boiled water, do some tummy rubs and make her run around a little.