Admob Android does not correlate to impressions to earnings

I have an app currently running on the market under beta testing. Everything was working fine until I realize I stopped earning money for a couple of days.

Is this something normal due to the decrease number of impressions? Or clicks?

Why does admob ignore completely the impressions I received?

Im worried that if I promote to the store ads will not work.

I appreciate any help!! Thanks a lot!

Screenshot of my admob report

There could be three reasons for this:

1. No one is using the app and there are no impressions at all
2. All the devices on which the app is running are added as test devices
3. There is a delay in admob statistics update. This happens more than often.

Update: if there are impressions but no clicks there won't be any revenue till there are clicks. Most ads from admob are CPC.