What is the ruling on money earned from the university and working with a university degree, if the reason for transferring to the College of Islamic Studies was "excess weight and inability to perform exercises," while the student is able to perform some exercises?

If the reason for your transfer from the college was written contrary to reality, then it is a lie, and you must repent from it. As for the reward and the money from the university degree, they are permissible. There is no harm in losing weight through permissible exercise. All of that has no relation to the lie. We advise you to turn away from obsessive thoughts and ask Allah for well-being.