do not worry.
If your songs purchased from iTunes, In the Apple official company FAQ, Apple originally stated that:
Synchronization occurs only in one direction, from your computer to your iPod. This means you cannot transfer music, automatically or manually, from your iPod to a computer(only for purchased music), and you cannot use iPod to copy a music library from one computer to another.
With the release of later iTunes , Apple revised the company FAQ to note (emphasis added):
Synchronization generally occurs only in one direction, from your computer to your iPod. This means you typically cannot transfer music, automatically or manually, from your iPod to a computer, and you cannot use iPod to copy a music library from one computer to another.
An exception to this is the transfer purchases feature which allows you to restore purchased iTunes
content to your computer from your iPod. Additionally, if you legally are allowed to copy music or other media files, you can configure your iPod as a storage drive to move media files.
The higher version of iTunes allow one to use an iPod to transfer songs purchased through iTunes to as many as five authorized computers. This only works for songs purchased through iTunes, not those ripped from CDs or downloaded from other sources, which are much more common.
This restriction was designed to discourage casual music piracy, but unfortunately, this also prevents one from easily copying legally acquired music from one's own iPod to their own computer.If you need to restore a music collection lost due to a system crash or want to transfer
thousands of songs to a new computer using your iPod rather than again rip hundreds of CDs, fortunately, there are a number of easy to use freeware and shareware programs that make it simple.
For MacOS X, try AVGo iPhone iPod to Mac Transfer http://www.iphone-transfer-sms.com/avgo-ipod-iphone-to-mac-transfer.html(Support iPod touch). For MacOS 9, try escapePod and iProber. For Windows, try iPod to iPod iTunes computer transfer http://www.iphone-ipod-to-mac-transfer.com/ipod-to-ipod-pc-itunes-transfer.html(and Support iPhone too,For Linux, try GUIPod as well as YamiPod (which supports MacOS X, Windows, and Linux).
Hope it helps yeah!!!