Please help me with this constant depression..?

I am a 17 Year Old Gay Male. I have been so incredibly depressed lately. Well, i have always been depressed and have always had bad anxiety but lately my emotions and depression level has been through the roof. I feel like dying, i can only focus on bad things. The MAIN thing that i have been crying my eyes out over for the last 2 hours is the fact that i am growing up. I think back and i don't know where time went. It feels like just yesterday i was little. I don't want to grow up.. my mommy is getting older, it doesn't seem real.. my niece is growing up.. my brother is almost 30, i can't believe this is happening. I can't stop crying.. please someone help me. I feel like committing suicide