When young we have lots of energy to replenish us..... as we age much of that energy reserve is depleted..... so we have to be take care of ourselves because we can't bounce right back like we did when young.  I have known many men in my lifetime who did just what you did and got over their flues....  they go out and get drunk and dance the night away and sweat it out of them.  I am slowly getting over this flu.... my nose isn't running all the time, although I am still coughing.  I am feeling fine though. 

"What lies behind us and what lies before us are small matters compared to what lies within us."  ~ Ralph Waldo Emerson ~