Iphone backed up different data and now all my data from before is gone how do I get it back?

So I hooked up my Iphone into the computer so I could put music on my Itunes and it said it didn't recognize the Iphone and that I should sync…'s Iphone on it. And I had the same name on it and I thought it was saying that my current icloud things needed to be synced but apparently it meant the last time I synced my Iphone on it when I had nothing on it, and it said to back it up and so i backup to find that all my **** is gone and that what it was like when I first synced it with nothing pretty much on it add synced on my phone and now all my **** is gone but the apps on it aren't. My hpotos, contacts, texts, call, everything expect the apps from the app store are gone. How do I get what was on before back.

You don't unless there's a backup somewhere like on icloud or your computer