Hi Jenny,
I think it depends on what you are doing and how strenuous it is. I don't know that there is any reliable standard that can say any amount is 'too much'. However, some activities require days of recovery. Serious weight training requires a rest day or two between sessions to allow the muscles to recover.
If you are comfortable with your workout schedule, go for it. If you find that you no longer seem to benefit from it, you should change it up some.
As you know the current wisdom is that people should get 30 minutes to an hour of exercise each day. That doesn't have to be a single session. I try to get at least 30 minutes of some activity almost every day. I normally take Sundays as rest days and if I think I need a rest during the week, I will take Wednesday off.
I hope some of this is useful.
Travis