First of all, my advice is to get a financial planner. Medical students are very dumb when it comes to finances and business sense. That is not a bad thing, though. We med students are good with the sciences! 🙂
Anyway, there are many things you can do to make ends meet. If you have a debt of $200,000 and your income is $38 - 40,000, you will easily qualify for a hardship deferment of your loans -- reasoning here is your high debt to income ratio. Whatever portion is federal subsided stafford, the Gov't pays the interest on that part during the hardship deferment.
Moonlighting depends on your program. Some programs allow it, and others don't allow it. You have to check with the individual programs when you interview for residency. In Illinois, you must complete your internship year (12 months) before you can sit for Step 3 and get an Illinois licence to practice medicine. So, if your program allows it and you have the time and energy, you can start moonlighting during your second year of residency and the pay is usually between $50-100/hour.
Good luck