GreenForThanksgiving's journey

I stopped working on March 20th and I’m feeling really stressed about my situation. I’ve never had to deal with unemployment insurance before, so I’m a bit lost. I didn’t file a claim right away because I was told I wouldn’t qualify, but after some research and talking to my employer, I found out that I was laid off through no fault of my own. Now, I’m worried about my finances as I won’t have work for another month while I wait for a hiring opportunity with my union. I’m wondering if it’s too late to file for unemployment and if back pay is an option. I really need some guidance on what steps to take next.