Sites no longer listed? (unsure)

Sites no longer listed in Google.

[Fuzzi_Bear]

I run 4 websites, all comepletely different from one another. Over the last couple of months, i have seen a deteriation in traffic, until now i have no traffic at all on any site. Whilst at the same time, indound links have been growing. I have searched for my sites in Google with 'site:mydomain.com' and all 4 sites seem there (so not a ban it seems), although all 4 sites deteriorated at the same time in terms of traffic. The odd thing is, i dont think im listed, despite the 'site:mydomain.com' showing results for my sites.

The keywords that i ranked not too badly on in the past do not display my sites at all. I then treid searcing on Google for specific/unique text on my site but STILL no listing my my sites in the search results. My sites are cached ok, but does that mean anything?

This has been the case now for a couple of weeks, and im at a bit of a loss, and not an expert in SEO at all. Can anyone offer light at the end of the tunnel?

Thanks.