Better you choose to take a day off now (and from what you've said, it sounds like a recovery day would do your body more good than another workout) than have your body leave you with no choice down the road. Believe me - it's extremely frustrating when you want to work out and you can't because you're injured or ill.
It's hard in the beginning, but consistency and quality really do beat pure quantity. You want to be exercising at this time next year, or five years from now, so it helps to find a schedule that's sustainable long term rather than burning through all your resources until there's nothing left in the tank.
Good luck, and enjoy your well earned rest day