"current reward - 0.0000140/Gh per day" . Well almost 5 days before there was 0.0000150 gh/s . Can we expect 0.0000130 reward after next 5 days ? Going low so quickly...
The mining rewards can vary from one day to the next. Profitability goes down when mining difficulty increases, but between difficulty changes, daily profitability varies depending on the luck factor.
I think you are misinterpreting things a little. It's best to use an independent profitability calculator, such as found on coinwarz, to get a clearer picture.