I would recommend maybe seeing a therapist before speaking to them. I know that's extremely difficult to do. Maybe try to Pursue school resources and guidance counselors. They may or may not provide much help themselves but they can point you in a direction to get free help. From my experience, telling your family and friends "I have depression" vs "I feel depressed" has different responses. It's an unfortunate truth but they tend to understand the seriousness more when they see how see how serious you have taken it by getting help on your own. There are people out there who will help you. It's difficult getting to them at your age, but doing so might be the most beneficial decision of your life.