In short periods stats can be delayed (click is counted, but not appear in the earning). But at the end of the day, you shall be oscillating around average.
i also have such invalid clicks sometimes. We cannot have control over this. Keep publishing, if you have no earnings for further clicks report to google. Never click your ad yourself at any cost.
It happens many times..no big deal i guess...but if most of ur clicks make 0$, then i guess its trouble