If, the router was on, then infact you are using it
info is still being passed between the internet and your router, albeit very very small pieces of info.
There is no problem, even if you havent used it, your msr will still be set properly (you hope), using the internet should have no effect on it, as its your router which is the connection to the internet and not your pc, so aslong as your router was on, then you shouldnt have any problems.
go here and do the test, and if you finally manage to get a result, post it back here, so we can have a look and see if there is anything to worry about.
http://test.speedtester.bt.com:50301/