Unfortunately, there isn't a ton of money to be made in the martial arts so a lot of schools run pretty close to break even. Throw in a string of bad months and suddenly the school runs out of money and has to shut down.
Most of the time, when a school closes suddenly it's not due to any malice on the instructor's part. Your instructor was probably desperately trying to find a way to pay the bills and just ran out of options. Instructors are afraid to tell their students about the financial situation because it damages morale and makes it even harder to save the school.
Still, your situation is a tough one. I know it sucks. But just know that you will find another home and be able to train elsewhere. Every good school that I have been a part of in the past has closed eventually; it's just how things go in the martial arts. Just be thankful that you were able to be a part of it while things were good, and try to keep that spirit going in your future training at other places.