Can you help me with my ipod (classic 360GB)?

I got this for a gift about a yr ago. I couldn't find the directions and now I finally figured out that I had to go through itunes..Before I thought I could just sink the music in by dragging it from my music folder on my computer. It took hrs to download all this music..Over 300 plus Cds I had on my hard drive that I copied from my cds a few yrs ago. I found out that it used up alot of the Memory of my ipod but it doesn't say there are any songs,,So they are transported on my ipod and I can't find or retrieve any of these songs I recorded . I didn't know that it could use up space and not be able to retrieve ..My daughter helped me a bit with getting them put on itunes....So I could put them on my ipod and they would be able to be played..I know have alot of extra space on my ipod used up in the extra part of memory.. But since I can't see what is on there I figured it is those lost songs I previously recorded ..(not through I tunes) Is there any way I can erase the extra space without erasing all the music and photos I put on it with itunes or do I have to format the whole ipod? I am so confused especially without any directions..Please help me if you can..I really appreciate any help you can give me. Thanks!