Two of our dogs acted similarly years ago.....the one who didn't go to the vet was actually foaming at the mouth. We were quite upset and concerned. Sadly, per our vet, we had to closely monitor them for safety reasons and give it time. It took several days (ugh) but things gradually got better and then all was well again. It was very shocking to us and we were so worried, so I can understand how you must feel. Best wishes to you and keep us posted as you feel able.