Hello, I Recently Purchased A Used Car, I Owe About 5000 Dollars More Than The Car Is Worth. I Recently Lost My Job. If They Reposses The Car Will I Have To Pay The Difference Or Will That Cancel The Loan Altogether

Discuss it with the people you owe money to. They may feel that once they have got the car off you they don't wish to pursue the other $5000, or they may not. In either case talking to them and admitting your fault and apologising for the situation is more likely to make them look favourably upon your situation.

Where did you get the loan, though the dealer, thought he bank, though a loan company, GMAC loans??

In general while they can take the car back if you go talk to them, and the car is in great condition, and call the deal even, most times they won't, but it is always worth talking to them.

This is of course why you don't even pay more for a car than it is worth, when you buy it. But yes and you can actually owe more than that.
What they do, is repo the car and sell it, and what ever they sell it for, the differnece is what you owe, and it may only sell for 1/2 of what it is worth, because they normally sell these at auction.

So you can end up some times after they add repo and legal fees, owing more on the car after they repo it, than you did before they repo it.