welcome to beyond blue.
Please read and re-read the above post from :/
secondly, the fact that you can post here is a good start. Being able to talk to someone can be very powerful. You can get a different perspective on things. It is unfortunate your parents might think that its just a phase, so my heart goes out to you, and as you live together the changes might not be noticeable and what goes on in your mind is not easily seen. (As you (read "I") get older we learn to wear a mask as a form of shield.)
Some links you might also find useful are....
Headspace, ages 12-25, also have a free online 1:1 chat here
Kids Helpline, anyone under the age of 25, have a free 1:1 chat here
kidshelpline.com.au/get-help/webchat-counselling and a 24/7 number 1800 55 1800
If it helps, continue to post here as well. You are not alone and there are many people who can identify with your experiences.