Bad credit rescinded offer

I just got laid off today (I’ve known it was coming so not a surprise). Received two great job offers and accepted one last week. They performed the background check (I’m clean and no criminal activity) but have bad credit history. I’m in the mid 500s. I have items in collections and charge off items. I’m planning on paying off collections by taking out my 401k when my job ends. I’m in accounting/AP industry. Now what? My personal life and bad finance choices should not reflect my professional career. I am a great employee, reliable, trustworthy and management level. I am so scared that I may be out of a job now for a while due to my bad choices. Someone please give me some hopeful advice. What do I do???!?