Thank you for relaying the VERY important information that she has already seen a few vets!! Your original question was brief and made no allusion to any treatment she may have received.
The fact that routine bloodwork is normal is reassuring to the extent that it means the kidney and liver have not sustained damage.
Nonetheless, more diagnostics need to be done... routine bloodwork alone will not give you the answers you seek!
I would highly recommend that she have a CSF tap or cerebrospinal fluid tap done to assess for any evidence of inflammatory, infectious, or cancerous cells in her spinal fluid.
In addition to ROUTINE bloodwork, it is important that rickettsial titers and screening for toxoplasmosis be done in your pet. Leptospirosis titers should also be checked!
Skull and spinal radiographs should be taken to assess for any possibility of a mass effect within the skull or spinal column. Any suspicious lesions would suggest that advanced diagnostics like a MRI be done to specifiy the lesion.
I would be sure that one of the antibiotics that she is on is Doxycycline in case tick borne disease is a factor for her.
Anti nausea medication may need to be given via injection to calm her stomach down. She may be vomiting more due to a nausea/seasick effect than a toxic effect.
I know you have already seen 2 doctors, but your pet sounds like it may require the services of a board certified internal medicine and / or neurologist. You should consider having your pet referred to a specialty practice or state veterinary school for a third opinion and workup.
I do believe your pet is very sick, and I regret that you are having such a hard time finding answers.
Best Wishes to You and Your Pet!
Dr. Jodi L. Smith