Awwwwww Minnie.
Sorry to hear about your flat tyre hun.
I very much doubt that you will have caused it any damage whilst riding. You would have to do a fair few miles with it completely flat to cause damage from the wheel rim digging into the tyre, so don`t worry.
Chances are you`ve just run over something. Use a car foot pump and pump it up and see if you can hear where the leak is coming from.
Occasionally a tyre may go flat for no reason, but if you can detect where the leak is coming from, draw a circle round it with a marker pen.
Hope you get it fixed