Vitamin C can lower blood sugar. Many of the symptoms you mention can be caused by a sudden drop in blood sugar. I probably would not take this much C at one time.
I started having some really funky symptoms when I increased my vitamin C about a year and a half ago. It took me a long time to figure out that it was the C that was causing them. I had no idea it had that kind of effect on blood Sugar until I ran across an incidental reference while I was doing some reading.