Let's be realistic here. You have some very serious health problems. You would not personally able to REALISTICALLY manage a garden alone without using Roundup, at least not this year. (The only other option would be to hire the initial cleanup done. However, you might not get spring crops in on time and you open yourself up to liability issues if someone gets injured on your property, or claims they were injured. Additionally, they might not do a good job with root cleanup of grasses, which you might be unable to deal with given your health conditions).
So, your options are
1) An application or two of Roundup before you begin this year or...
2) Buy your veggies. Given your current financial situation as a result of these surgeries, you probably could not afford organic veggies. Thus, you would be buying pesticide laden veggies. These would almost certainly have been grown using Monsanto (or other similar giants) products, including the high likelihood of Roundup or worse products...
I'd say that the initial application of Roundup is far better than having to buy all those veggies from the grocery store. Any small residual amount of chemicals that MIGHT make it into your food will be far less than what you would take in from store-bought veggies. Plus, you'll be able to get some exercise and activity while doing what gardening you can thus gaining in health benefits in another way.
Sometimes you choose the lesser evil, which is what you did.