Just to put things in context, a pound of fat represents around 3500 calories.
Running burns around 140-150 calories per mile, so maybe you burned 700-750 calories. 3 ounces is probably less than the margin of error in your scale anyway.
And I am assuming that you didn't eat an extra 6500 calories afterwards.
Day to day shifts in the scale are almost always water weight. And yes it is a very common response to increasing an exercise program for your muscles to retain water.
As for "didn't sweat much", this is a very subjective measure. In low humidity conditions, with a bit of wind about (or creating your own wind through running), it is possible to stay cool, sweat quite a bit, but for the rate of evaporation to pretty much equal the rate at which you are sweating, so not really experience a noticeable buildup of sweat. 1.5 lbs of sweat loss in 5 miles seems quite feasible.
The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.
| current weight: 178.0