Need Help

We haven't posted in a while but, I'm in need of advice. We think one of our bassets had a siezure tonight. She made a noise between a howl and cry of pain. My husband went down stairs to see what was wrong and found her convusling on the chair. Her legs were going like she was struggling to get up and struggling to breathe. He put her on the floor and checked to she if she was choaking. He kept his fingers in her mouth and after a minute she swallowed hard and started breathing normal ( a little fast but steady). It took her a minute and she blinked and started to wag her tail. She is a little restless now but ok. We are taking her to the vet in the morning unless she does it again. Has this happened to anyone else? We are very scared and trying not to think the worst. Can anyone help?