What happens if I take too many Vitamin C's?

Shaklee's Chewable Vita-C, (dietary supplements) taste really good. They inhance your immune function and each tablet is equal to 1 and 1/2 oragnes. I have a bad cold and haven't taken these vitamins for a year, and they taste soooo good I just ate a whole bunch. How much is too bad, or is there no limit?