First thing, you are responsible of keeping track of when your I-20 expires. Secondly, you can take classes outside your major but once you change your major, you are supposed to go to the International Services at your university and get a new I-20.
Before blaming the counselor, you need to think if you were keeping track of things for yourself. Expecting your counselor to send you emails saying things like your I-20 is about to expire and you need to get a new I-20 because you changed your major is foolish.
However, it seems like there is a solution as your counselor pointed out. Go and talk to him/her and apply for reinstatement. This is pretty tense situation for you but stay calm and cooperate, keep your anxiety and rage under control.