Using marijuana in a state where it's legal to use only means that the state and local government can't prosecute you for using it. It does not take away an employer's right to refuse to employ people who can be shown to have used illegal drugs. Marijuana remains illegal at the federal level. So, while a state may decide not to prosecute you, if the state decided to pass a law that prohibited an employer from terminating employees who test positive for a substance that is illegal at the federal level, it would be ruled unconstitutional.
That is why no state has passed such a law regarding employer drug tests, and if your state's unemployment department will not pay for terminations for just cause, like your termination, then you aren't going to collect. What does your state do? How could we know; you didn't tell us the state? Apply, and if denied, appeal.