I am about to lose my current job and offer from another company

I've leaving on a bad terms with my current company, because im leaving in an earlier date than i supposed to. New company was pressuring me to start early. So now when im about to start my new job on next week, HR from new company messaged me with requesting a recommendation letter from my boss. They say , they want to make sure that i'm leaving on my own terms and not being fired for under-performance, etc I guess i'm out of luck here? I am afraid of losing an offer and leaving the company, and becoming unemployed