It sounds as though you could skip the Ritalin altogether for a while. You don't want to stop and start medications while you are recovering. The best thing to do is to decide whether you want to keep taking it or stop taking it and stick to your decision so that your brain can readjust to either condition. Switching it up is only gonna make it harder for your brain to heal itself.

I can't imagine going through withdrawal and having PCS at the same time. I feel for you, I really do. Hang in there buddy!