I keep losing everything everytime I connect, WHY?

Over the past 4 days I have spent at least 12 hours putting some of my cds on my 60gig iPod. I insert the CDs, import them then update my ipod and I am off. Before I deleted the files in my library, I export the files and save them to my computer HD. When I reconnect my ipod, of course the contents of the ipod is erased. I import the file I saved and nothing happens. So I have to spend another 3 hours putting the cds back on my machine. I share a computer with my daughter and am not sure how manage my files without losing everything everytime i connect. What the heck is going on? I have many CDs i would like to move to my ipod, but do not have 40 hours a week to keep up loading them again and again. Please help me, why do I keep losing everything?? Can't I simply upload them once and forget about them? HELP!!