Confusssed about job what would you do?

I have been in janitorial work for some time now, i have been cleaning car dealerships for a little over 2 years. I quit my job this past Sunday because i just can't take the physical pain no more. The jobs are not hard,but it's getting hard on my neck and nerves. My boss wants to give me my job back(even though i did not ask). I know this is a question that no one really can answer because it's up to me,but would appreciate input. I filled out 3 apps.today for jobs not so demanding on my old body,i know that dosent mean i will get any of them. We need 2 incomes in our household,but i just can't take that work no more. I will feel guilty if i get no job,needless to say we will barely be making ends meet again. I have not missed 1 day of work in over 2 years of doing this. Maybe i just need a rest. But the thought of going back really does not appeal to me. What would you do? I'm going to be 56 in December.