Hello Bonaseraj: I understand your financial constraints. At this point, if she's scratching herself to the point of bleeding, I'd be thinking about trying steroids. Your vet already examined her and checked her out so it would probably be okay for your to just call your vet in the morning and tell them everything you've said here and ask if you can pick up some steroid pills to try. This should not cost any extra exam fee, just the cost of the steroids which are not expensive. If your vet says they want to do a recheck exam, it won't cost very much. Sometimes it's necessary to do another recheck prior to starting steroids just to make sure it's not fleas or mites even though they already checked once. Fleas and mites can reproduce quickly and be visible on a recheck exam even if they weren't visible on the first exam. Also, I usually treat these itchy dogs with a medication called Revolution which kills fleas and mites, just in case there is one tiny flea or one tiny mite causing your dog to be itchy. So, ask your vet if you can just pick up some steroids and a dose of Revolution. If they say yes, see how that goes. If they say you need a recheck, bite the bullet and go for the recheck because your dog won't get better until the problem is treated appropriately. So far, antibiotics and antihistamines are a reasonable first start at treatment, but now it's time to try something else. I hope I've answered your questions. Let me know if you have more questions. Best wishes.
The best answer to any question regarding a sick pet will come from your own veterinarian, however, I am happy to provide information based on my experience.