
I know different breeds lifespan can differ so 5-6 in my breed is still very young as they mature late and can live to 16 or more years. Some breeds 6 is a good age .
A change in behaviour at this age I would have her checked out by the vet just to make sure everything is ticking over nicely.
Has your routine changed at all a friend of mines dogs get quite upset when the whole family are taking leave from work as it upsets 'his' routine.
Is she due a season ?