I am feeling absolutely exhausted.

Did the 5 day isolation, fever only lasted a day and the other symptoms are practically gone. But now I feel completely zapped of energy. It may simply be due to being a bit more active today than I've been in the last week (our family started feeling sick about a week ago; I came down with it a couple days later). Is it normal to see a reduction in energy 5-6 days in? I don't have a shortness of breath, dizziness, etc. that would make me worried about pnemonia. Just the tiredness.