My 10 year old tabby has always vomited or dry-heaved after rapidly eating her dry food (IAMs weight control), she's never liked wet food or any other foods.

Her coat has always been rough looking and full of shedding dander, with a oily strip down her backside. She's about 20 pounds, and has trouble going up stairs in the last few years.

Lately I noticed her drinking lots of water, and when i came back from a weekend away, found vomit piles all over the house (some with fur in it, unusual for her). During the last 2 days, dry heaves every 15-20 min, and doesn't meow for food (unheard of). She seems to be swallowing while she heaves, and last vomited a puddle of slimy clear salvia. She seems to be in pain when picked up, and will heave or convulse when she tries to purr. I can't see it being a hairball, for her vomit usually has no trace of hair and i've never actually SEEN a hairball.

My cat is quiet, not asking for food, and very sick...please help! I'm hours away from a vet, and can't possibly get her to one til the weekend.

I regret that I cannot make a specific diagnosis on this site. However good a description of the signs is made, a proper physical examinatuion is required.
The only comment I would make is that your cat does sound to be very overweight - that contributes to a number of problems.

Thank you for responding! She seems to be taking a little water and a little tuna oil-soaked food in tiny amounts...the dry heave-swallowing seems to be lessening, but yes, you are right, it's high time for a check up on my poor fat ol gal. I sure got a little scare from her yesterday, and thought "this was it"...something none of us are ever quite ready for