Are you trying to puke on purpose to lose weight? Is that why you drink soda and coffee? The zero sugar part doesnt matter, you could drink full sugar - the acid would STILL irritate your ulcerated digestive tract.
Purging aka puking works for a while, theoretically, but then it wrecks you. I think you are at the wrecked state, whatever the cause of your puking.

Either you are exaggerating here, or severely obfuscating your symptoms from your drs.