My dog has no balance?

I recently adopted a 6 month old pug and she is very energetic. Earlier today she started throwing up foam and had no appetite. She seemed very tired and slept for a couple hours. When she woke up she had a unusual burst of energy so I took her to the dog park to burn it off. 2 hours later she seemed as if she was stumbling and her balance is off. When we got home she went to drink water and just falls into her bowl and she struggles to get up and bobbles her head. If i play with her and she runs, she seems fine... I don't know whats wrong. Are these signs of an on coming seizure? I'm going to the vet in the morning, but I need an answer now. Please help..