Hi Laurie, welcome to the board!
I am sorry your son has been sick for so long. It is good he has been diagnosed so he can get treated. What does his rash look like? It is important to get photos of any rashes. Place something near it, like a coin or ruler, before photographing to give it size definition. Then you have evidence of it.
Below is a Lyme symptom list. You can have any combination of symptoms.
Unexplained fevers, sweats, chills, or flushing
Unexplained weight change--loss or gain
Fatigue, tiredness, poor stamina
Unexplained hair loss
Testicular pain/pelvic pain
Unexplained menstrual irregularity
Unexplained milk production: breast pain
Irritable bladder or bladder dysfunction
Sexual dysfunction or loss of libido
Change in bowel function-constipation, diarrhea
Chest pain or rib soreness
Shortness of breath, cough
Heart palpitations, pulse skips, heart block
Any history of a heart murmur or valve prolapse?
Joint pain or swelling
Stiffness of the joints, neck, or back
Muscle pain or cramps
Twitching of the face or other muscles
Neck creeks and cracks, neck stiffness, neck pain
Tingling, numbness, burning or stabbing sensations, shooting pains
Facial paralysis (Bell's Palsy)
Eyes/Vision: double, blurry, increased floaters, light sensitivity
Ears/Hearing: buzzing, ringing, ear pain, sound sensitivity
lncreased motion sickness, vertigo, poor balance
Confusion, difficulty in thinking
Difficulty with concentration, reading
Forgetfulness, poor short term memory
Disorientation: getting lost, going to wrong places
Difficulty with speech or writing
Mood swings, irritability, depression
Disturbed sleep-too much, too little, early awakening
Exaggerated symptoms or worse hangover from alcohol
It is very important to see a knowledgeable doctor. 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. Has your son been tested for these?
I believe both Lyme and Bartonella can cause anxiety and insomnia. To see some neuropsychiatric and cognitive symptoms of Lyme in children, go to Lyme Disease Research Studies Overview of Neuropsychiatric Lyme Disease at http://www.columbia-lyme.org/flatp/lymeoverview.html
It is very important for him to take the meds as prescribed or they may not work properly. Be 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 worse. It can be scary when it happens, but it is a sign the antibiotics are working. Although this reaction can vary individually, many people experience this at the beginning of treatment and every three to four weeks. This may be what he is experiencing.
During treatment, it is good to document your son's symptoms daily. One way to do this is to list the three main symptoms he has each day with a numerical rating of their severity from 1-10. Over time when you review this, you can see when his herxes occur and how he is responding to the meds.
Doing things to strengthen his immune system is important--eating healthy, drinking a lot of water, getting exercise whenever possible, taking appropriate supplements, and doing things to detox. It is also important to learn as much as possible. I recommend reading Dr. Joseph Burrascano's 2005 Diagnostic Hints and Treatment Guidelines For Lyme and Other Tick Borne Illnesses at http://www.ilads.org/burrascano_0905.html He is one of the top Lyme doctors in the country, and many Lyme doctors follow his protocols. He also lists diet, supplement, and exercise recommendations. 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. Singelton MD.
Hang in there okay? Good help is available. Your son is lucky to have such a caring mom.