IPod Touch Help Please?

Ok, so I have a really really old version of the iPod Touch and I just went on iTunes and updated it. Now I don't have any of my games or anything else. I also don't have my installer. Where did it go??? And how do I get it back? Is there a way? Do I have to jailbreak it again? I still have YouTube and Safari and stuff. I'm so confused! Help please! Thank you!