The treatment for anxiety is a multi-modal approach - intervention, therapy and possibly medication. Zoloft is an excellent medication for anxiety; however, it should be used in order to "take the edge off" of her anxiety. It will never "cure" her anxiety (the hard work is done in intervention and/or therapy) - I think I would seek another medical professional - perhaps one with experience in anxiety disorders. I wish you the best ...
Is pressure put on your daughter to do well, if you and she are competetive could be she feels she has to do well all the time, thats a lot of stress, I would ask the Doc who prescribed Zoloft to evaluate again and make sure she does need it,The fact ahe crys when you turn up show it is related to wanting to please you, back off a bit , let her go to her ballgames alone for a bit ,make sure she does other activitys that arent so competitive and there is fun in her life.