It's not that you can't handle it. Maybe you should just focus on one thing at a time. Why would you want to foster animals when you already have sick ones? I know if I was running a rescue and one of the people wanting to foster my birds had sick animals at home and were too busy trying to bring more animals into that house to foster I wouldn't do it. It's just a bad idea.
What this has to do with your single, sick reptile is that your single, sick reptile is sick because of improper care because you're not paying enough attention and didn't do your research. And your other hopefully still healthy reptile is being exposed to the exact same conditions and the sick animal. What do you do when you have one animal with a potentially contagious disease and one healthy one? You separate them. They should hvae been separate from the very beginning. You can't pony up the $12 for two tubs, or you refuse to because who knows why. You obviously don't know what you're doing and are refusing to listen to the people who do know what they're doing and who you came to for help.
We're trying to help, that's all. We're not attacking you as a person. We're maybe questioning your judgement and your decisions but not your capacity to handle stress.