Lost ranks in google today with many sites

So, i've heard that it is bad to link sites together which was on the same IP address. I have a dedicated server which I run most of my adult blogs on. Today I seem to have lost ranking on 90% of my sites (a lot were on the first page, now nowhere to be found). I installed a google sitemap wordpress plugin on one site which ranked #4 for its term, Since then it seems they all dropped off. Did google change something today? Did the sitemap screw me? Am I an idiot for hosting them all on the same hosting package? I am pretty new to SEO and was rather happy I was able to get my sites ranked, Now it seems they are gone. Does this happen from time to time? Maybe if I am lucky ill be back there tomorrow. Any input would be greatly appreciated.

 

Wait a few days and see what happens. I would start some new sites with different adress from now on.

You can also get more links to each site from other sites not your own. This can help if most of your links are from your sites.

 

Yeah I know about building backlinks and such, But I run a network of PR4 sites which tend to get me great ranking in google rather quickly. Seems they may be catching on to this though Thanks for the input

 

You also have to take into consideration most often when you update your site you should resubmit it to search engines again so the tags & key words will be recognized. It always helps to stay up in the rankings.

 

Well most of the sites I am referring to are wordpress blogs with fully modified themes. I generally ping some services each time I add a new post. I never submitted these blogs to search engines in the first place, Simply linking to them on my PR sites got me listed within a few days on google and others over the following week. Any suggestions for this?