Your lawyer is right.

You just filed I140, but then if you filed status transfer from F2 to F1 then you are overwriting your I140. You'd better consult the international student office of your school if you use I140 to study. However, if you filed I140/I485 after 180 days (if I remember correctly) and haven't received any results you are eligible for apllying AP and EAD. You can use AP to travel, probably you can use it to go to school but you ned to confirm it with your ISO.