Website question

The past couple days I noticed that the traffic to my website was cut in half. I've seen it happen before but after a day or 2 it jumped right back up to normal. So I started doing some digging. All my traffic sources look to be fine but then I put my full website name into google and it didn't come up. So does this mean that google slapped my page 15 worlds away or are there some changes I need to make in order for my site to list. I would think that when I type in the full web address to my site that it should still get pulled up.

Edit: Just thought to do a direct search ie site:http://........ and nothing came up. So that means somehow all of my pages became not indexed in the past couple of days.

Any suggestions?

You should do this command in Google:
site:www.yoursite.com and see what happen. It should answer you with all the indexed pages of your website.

If there are no page, this means that you have been penalized, also try to figure out if there are some pages missing form the index that in past their was there. However it sound odd if you don't have any traffic changes.
Anyway, you should look also to your analytics and in traffic source look for the Google traffic.
And in the webmastertools you will see the average position in serp, and see if there are some keywords that lose power.

And see if it changes recently.

If you have been penalized you should consider to check for PBN links and spam links, too many links with exact matching keyword, duplicate contents, low quality contents, and ask yourself what have you done that can be penalized.