Complete website update transition / rankings

Already have great rankings, but will an update effect this.

[floridadesigns]

My website is all optimized, and has many great rankings in search engines. This took me a long time to generate, and now that have an update planned for the website, I'm afraid that I may lose some.

The new site is completely new, and was created with better organization, and naviagation. I was wondering whether updating all of my pages could result in a loss of ranking?
Or if anyone else has already done this, and what happened to them.

Thanks alot, I really appreciate any help!

[korkus2000]

Did you change file names? Changing the content structure will effect rankings.

[charpress]

Yes, I'm afraid it probably will.

I did the same thing last month and saw my ranking drop about two weeks later. I tried to do things without losing pages --to at least keep page names the same so the spiders would not get confused.

I'm just hoping at this point that it is a temporary glitch and that things will even out and I'll go back up.

Every time I do something to try and improve the site or improve rankings, I usually get a drop. I've about decided to give up trying to please Google and just please myself.

Maybe I'll even drop the Google bar from my browser so I'm not constantly reminded.