Please, this is an urgent situation for me and my chihuahua!?

My dog, a small long-hair chihuahua, might have problems. She just, and this is the third time, had symptoms of panting, pacing, seizure, tail tucked between her legs, drooling, and I know this is very serious, but we just don't have enough money for the surgeries that could happen. We haven't taken her to the vet for emergency as we know that it is very costly. What should we do? I'm very scared and I think these could be really bad problems with her. She is better, but shaking and I've laid her on a soft pillow. She's three years old, human years, and I don't know what to do. Should we put her to sleep or euthanize her at the vet? PLEASE HELP