problem getting mortgage

My wife and I are in the process of selling our house and are having difficulty in qualifying for mortgage for a new home. We have never been late on our current mortgage and both have very good credit scores. The problem: my income goes up and down radically and last year was a down year so no one will approve a mortgage which seems strange to me. We should clear about $200k when we sell our current house and want to use the money to clear up some debt. I had cancer and was out of work for over a year which means that we accrued debt but have never been late a single time on any payment. We want to use the money in our house to stabilize our situation and we would still easily have 20% to put down on a lesser expensive house. We feel that we have been very responsible and by cutting our mortgage payment roughly in half, we have a very solid plan. What options, if any, do we have?