On interpreting the statistical significance of R squared
The p-value is the strength of evidence against the null hypotheses. In this case the null is that the coefficient is equal to zero. So your p-value says that this is very weak evidence against the null so you model is likely to be describing the underlying system of the data.

R-squared describes the percent of variation that is explained by the model. Your value is very low; 14.5%. Of all the "activity" in the data your model is only explaining 14.5% of it.

So you have a situation were model is most likely explaining variation in data but not explaining very much of it.  I would suggest altering the model and refitting.