I to understand you all to well... I did not understand depression either when I did not know anything about it. Then wham 10 years ago it hit me. I have not dug out of my hole since. Even before this I suffered from depression and did not know it.
But it would only last a few weeks. Now it is a fight to go on every day. Can you get them to read a self help book on depression? Can you get them to go to your doctors with you? Print your post out and share it with one of your loved ones. Maybe they will understand. Good luck,, welcome to PC,, You are not alone..