I second the vitamin C statement... Take several small doses throughout the day. This is better than one big dose.

I would also second the statment about stopping all supplements, then add them back one by one to find the culprit. Make sure you wait at least 4 days (a week would be better) with each new supplement to be sure what the effects really is. Also, keep a journal.

Everything has a cause, finding it is paramount.

Keep us posted.