Like others have said, it's going to be all right and you will figure out how to take care of your diabetes while living a normal life.
I loved theatre and acted in a number of plays in college. As an adult, I earned a living as a stage hand and stage manager in Chicago. You can totally do theatre with diabetes. The tough part with doing it professionally is that you have no health insurance, which finally made me give it up for a more traditional job.
There are a ton of good D books. The must haves are:
Think Like a Pancreas by Gary Scheiner
Using Insulin by John Walsh (he also wrote "Pumping Insulin" for when you're ready to try a pump)
The Diabetic Athlete by Sherri Colber
50 Diabetes Myths That Can Ruin Your Life; And the 50 Diabetes Truths That Can Save It by Riva Greenberg
Make sure you have a doctor who you like and who will talk with you about real life issues. When I was a teen my doctor talked with me about how to bolus while drinking, diabetes-friendly birth control, and managing D in college.
If you have insurance I also really recommend trying an insulin pump. It allows you total flexibility to skip meals or correct a slight high blood sugar.
I'm middle aged now and have a healthy son and no diabetes complications. I've traveled extensively and in my younger days loved camping and outdoor sports. There's no reason you can do anything you want with diabetes, you just have to do it a little differently.
Take care and post any questions you have as they come up. -Jenna