Those "over methylation" symptoms are possibly hypokalemia or pottassium deficiency which is life threatening.
I have started Freddd's protocol and he heavily cautions to watch out for that when beginning, have some pottassium on hand and be cautious. I am really learning a lot about starting methylation from him and here is the rundown of what to do:
check it out, it is very very interesting and helpful. He has worked with lots of people going through what you are experiencing, his protocol is very methodical...good luck!