Your teen years are such a strange and difficult time for a lot of people - they certainly were for me - and depression is pretty common too, so you are absolutely not alone in this.
Talking about it is always going to be hardest in the beginning, but it will get a little easier each time. It's worth the discomfort if it means you can get help. I want you to know you have made a very important step by simply posting this asking for help online, not everyone is able to do that, and it's great that you've figured out that you need more support from the people around you.
I know it can be hard to know what to say, but the best thing to say is usually the most honest. You can start simple by saying how you've been feeling (sad, angry, depressed, numb, etc.) and if there are specific reasons for those feelings and you feel able to talk about them, you can do that too. You can also say "I really need help" or "I don't know what to do". However you're feeling, for whatever reason, it's ok to feel it and it's ok to say it.
I think you can do it, and I hope it goes well, whenever you feel ready.
I'd also like you to know, from my own experience, that it truly can get better. And not just a little bit better, but a lot better. I have had depression for most of my life, and it has been severe at times. My life is really good now :) I have tried a few different medications (prescribed to me by doctors), therapy, and even a new treatment where they use an electromagnet! it's been a bit of a journey, but each type of treatment has been worth trying, and now I have a combination of things that work well for me, and now I have way more good days than bad.
One of the most important things that has helped me, though, is having supportive people around me. My mum, my partner, my friends and my therapist are all important parts of my support network and I know that if I end up in a really dark place again, I have people who will catch me and help me out of it. So, I really hope you can find that kind of support from the people around you, too. The first step is just to ask for it.
I might be just a stranger on the internet, but I'm cheering for you :)