Ps: I am not a lawyer or a counselor but only providing some informations based on my experience.
as I know it can be very hard to be patient , especially when it comes to finding a job and the fact that you already secured one. But here is the thing , as I understand , once you have the 6 months Ausweis , abs are generally allowed to work , then the other permit comes from the Agentur fur Arbeit , and what they usually do is to compare if the working conditions are met generally - in terms of compensations, working hours and that you’re not being cheated or given a particular job for a particular reason. This usually takes anywhere between two weeks to one month or even longer in some special cases.
My advice: be patient , talk to your employer , and let them know the situations and see them to understand, the other thing which I can advise is you can visit the Ausländerbehorder and try to find out the progress so far as it was sometime like that in my situation. The Ausländerbehorder can send a reminder to the Agentur fur Arbeit and it and can resolved quickly. but generally be patient , it will all be fine and I’m sure you wouldn’t loose your job. We all felt same way one time or the other.