Should I give up my istant manager position?

I work as an istant manager at a large music instrument retailer. It is a full time position with a lot of responsibilities that I have been doing about 5 months. The problem I have is that I still working on 100% commission. Because of all the responsibilities I have I have little time to sell and average about $550 per 80 hour paychecks. The position would be great if it was an hourly wage, but the stress that I have to go through for so little pay when I can not get much commission does not seem worth it to me. The thing that bothers me most is that when I was just a department manager with much less responsibilities I was averaging $1,500 per 80 hour paychecks from commission. This is not a job I want to make a career, its just a job to get me through college. Should I give up my AM position and ask to return to DM?