Just got off of two years of working second jobs. Worked retail for about 8-9 months. (at a 24 hour super store, not Walmart thank god) So I would work my regular job and then work 6pm to Midnight or 1am at the service desk and then weekends. The money came in great for groceries and gas but was only about $200 a week.
My other second jobs all had to do with my primary job which is a social worker. I was able to get paid quite well picking up extra work for a couple of neighboring counties who didn't want to hire full time people to cover some extra clients. I did that on weekends and was able to make about $300 a weekend (but it wasn't always steady some weekends there was no work)
Can you do any type of in home care? Some agencies need people who are willing to take care of elderly people in the evening but it doesn't allways pay well. Can you mix drinks? Bartenders can get good tips. Work at a staduim for sport events or concerts. Good luck it's great owning a house but the debt does get to be a hassle sometimes.
And yes it was unbearable....well the working retail was, I was always tired and was gaining weight due to snacking to stay awake. If you have kids, it may not be worth the extra hours if you can stand to pay down the debt a little at a time (I'm not sure how much the debt is) but if it's food we are talking about then working extra time is do able. I didn't mind working the extra social work hours on weekends because my evening were usual free then for family time.