Dear Artist,
Let me start with reminding you about the importance of your health. I'm not going to tell you to eat better or work out, because I could do some of that myself. However, this is about sleep. That whole "you'll sleep when your dead" mantra is for the birds. Your body is so important and the there's not much that your body can do on an empty tank. Get whatever you can done during the day and get yourself to bed.
I'm also going to stress the importance of knowledge. You need to be reading books and plays, practicing, and taking the opportunity to see work. If you have the means to do so, there is no excuse to miss out on a piece of art. I have heard of two many artists who don't feel like sitting through a play. Or they find themselves too tired to make it to all of their acting classes. You may not be majoring in biology and have to sit in your room studying all night, however your experience takes that place.
Everyone wants to be an artist. There are countless people with beautiful voices and even more with acting skills they were just born with. What sets you apart is your work ethic. Get your butt in that practice room until that run is right. See a play that you hate and figure it out. Work through what makes you dislike the piece so much.
While taking care of yourself artistically is important, your financial health is equally important. Do not be a starving artist. You don't have to give performances for the exposure. You don't necessarily have to be a waiter or a temp, but find something you love outside of your art. There are plenty of opportunities to be a nanny, substitute teacher, or a professional organizer. You need money. End of discussion.
You should be learning how to check in with yourself. Our bodies and our minds are so essential to what we do.