To regenerate stamina you can do a little something like this:
Basically I’m adding a boolean to the code so we can always check anywhere if we’re running right now or not.
If we are running it will reduce the stamina as we’re used to but if we are not running it will regenerate stamina by our set amount (1 again in this case).
I had to split it up into two comments because of the 2k character limit 
I hope this helps you. If you have any question about anything I did don’t hesitate to ask!
Cheers!