Good for you for doing it!!  She needed the shot and there is no reason to be afraid to give it.  I know that you don’t want to cause her pain but to not give it due to your fear is really unfair to her.  I believe that if you are alone and she needs the shot you will be able to do it.  Practice on an orange and feel confident.   Next time, is there a neighbor who could come help hold her still while you give it!  Anyway, thank goodness she is doing much better.  Julia