I think everyone goes through this, but there may be something you can watch for besides the bushes.
If you are a new caster, you may sometimes get a "buggy whip" effect when you are casting.
If you hear a SNAP sound behind you, it is because you are dropping your back cast too much. This can snap your fly off if you are using a lighter tippet, it used to happen to me when I was first learning.
Good luck, it will get easier as time goes on.....Kerry