Will the wii mess you up in actual tennis?

Okay so I am a freshman beginner in tennis at school. at my first practices I was pretty good for my level. Then we had a 1 month break period so I wanted to get practice so I played wii sports tennis. I tried not to flick my wrists and I thought i was getting better. Then I had my first practice today and I was more worse than before. I couldnt get the stances and positions right. Could it have been the wii that messed me up?