My dog keep vomiting...?

Ok, I have a small 5 year old miniature dachshund/miniature poodle/min pin mix & for the last two days she's been excessively been throwing up her food & afterwards a yellow fluid. It was about seven or eight times yesterday & four times today...tonight was the worst as she started yelping & crying; she stopped a few minutes after much reassurance from me...poor thing. Anyways, I'm on disability & there are no clinics that will work with me on a payment...they say I'm on my own. She's been drinking water & seems as cheerful & lively as ever...she has been lazy...but that's typical with her. I know no one here can give me the information as to exactly what's wrong with her, but does this sound life threatening? Her vet said it could be her diet...which probably doesn't help due to the fact that she had a severe case of gastritis when she was a puppy (I don't know if that's a permanent condition with dogs...). Anyways...is there possibly any at home remedies that may help? I know a vet is best, but it's not an option for me right now...