A.S.
I whole-heartedly agree with the suggestion of Dr. Bock's book - he has a very interesting discussion in there about PANDAS. With any luck your library will have it.
Our son never had it "officially" - back then we didn't know about it (neither did most physicians). But he went for a spell in Kinder where he had strep 4-5 times. It was awful.
One of the things that helped him the most was to strengthen his immune system overall. We found out he is severely intolerant to gluten, and removed that from his diet. He's also sensitive to dairy but that seems to be getting better. He has other food intolerances, too, including eggs and chicken.
I would also research candida (yeast) - our son was on multiple antibiotics through the years. Yeast can weaken your immune system too imho.
I'm not a health care professional of any kind - this is just my "mom" opinion. Furthermore, we made very little progress with our mainstream ped. It took an integrative physician (an MD) to get to the heart of our son's health issues.
Today he is 14 years old - 6 feet tall - and a black belt in karate! (Thanks for indulging me - I'm so proud of him. He was so sick for so long).