Okay, have you been keeping an eye on your ammonia level? What is your water chemistry like? Because this sounds like ammonia poisoning. If your fish are super lethargic and lazy, have a decreased appetite, and just lay in one place, it's probably ammonia poisoning. Check your ammonia level, as well as nitirites and nitrates and pH, and see if that is your problem. If it is, you should be performing PWCs very often til the ammonia decreases.
I know you realize that your tank is too small, and as somebody making minimum wage, I can understand. However, goldfish have fast metabolisms, and create a lot of waste. This increases the amount of ammonia in the water, and in such a small tank, it will quickly kill your fish. Look on Craigslist, your newspaper...anywhere, and transfer them to a 10g MINIMUM as soon as you can. In fact, you're going to need a larger one in the long run. I'm transferring mine from a 29g to a 55g as soon as it cycles.
Keep on those water changes!
I know it sucks when your goldfish are sick. My goldies are my BABIES!
Good luck!