[Help] My website keywords disappeared from google search!

As the title says, my keywords (about 30+) ranking on the first page of google!
This has happened to my site some few weeks ago and then within 12 hours it came back to the normal position, but this time around it has been 48 hours and it is nowhere.

Here is a little info on my site.
1. No, it is not google dance, the site is about 7 months old now.
2. I have no build any link to the site for some few months...
3. I checked WM and no warning whatsoever.

Please can anybody tell me what else to do or check?
Thank you for your replies.

Did you purchase any links?

It happens on every site of mine that is 3-1y old.

Link dissapear and appear again after 10 days on lower or higher position.

Do not worry, it will come back or not, it's not end of the world.

get your self a serp tracker so that you can view your trend and find out what is causing it!

Maybe its just dancing,as sashablack said,get yourself a premium serp tracker like serpbook also.

The same happened to me.
Seventh month old sites suddenly disappeared.
One is hit 28.06 and the other 15.07.
Home page is nowhere and internal pages have fallen on page 10.