Hi dejavoodoo, welcome to the board!
I am sorry you have been sick for so long. below is a Lyme symptom list. You can have any combination of symptoms.
Besides Lyme, ticks can also transmit several co-infections including Babesiosis, two types of Ehrlichiosis (HME & HGE), Bartonella, and Mycoplasma. Many people who have Lyme are co-infected. It may affect treatment choice and progress. It is important to be tested for these by a Lyme reputable lab such as IgeneX in Palo Alto, CA. Have you been tested for these?
I agree that 500 mg of Ceftin is a low dose. A higher dose is typically prescribed along with another antibiotic. Are you seeing a Lyme knowledgeable doctor? If you need a doctor recommendation, you can email me.
Are you aware of the Jarisch-Herxheimer Reaction (herx)? Often when people who have Lyme take antibiotics their symptoms get worse or they get new ones. When the antibiotics kill the bacteria, toxins are released making them feel sicker. Although it can vary individually, many people experience this at the beginning or change of treatment and every four weeks. During treatment it is important to document your symptoms daily. One way to do this is to list the main symptoms you have each day with a numerical rating of their severity from 1-10. Over time when you review this, you can see when your herxes occur and how you are responding to the meds.
It is also important to learn as much as possible. I recommend reading Dr. Joseph Burrascano's 2008 Diagnostic Hints and Treatment Guidelines For Lyme and Other Tick Borne Illnesses at http://www.ilads.org/lyme_disease/B_guidelines_12_17_08.pdf He is one of the top Lyme doctors in the country, and many Lyme doctors follow his protocols. He discusses antibiotics and doses starting on page 18. I also recommend the books "Everything You Need To Know about Lyme Disease Second Edition" by Karen Vanderhoof-Forschner and "The Lyme Disease Solution" by Kenneth B. Singleton M.D.