It’s like I’m two different people

How is it that I speand my nights sad, confused, and unsure about my will to live. I currently don’t think I’d ever actually do it, but I’m beginning to wonder if one day soon I will.
How can it be that I live my life appearing so happy and strog minded to everyone who knows me when really I’m so confused and unhappy on the inside. If I killed myself tonght, everyone I know would be so shocked and confused that the happy, friendly kid who is always joking around committed suicide, yet somehow in my own mind the idea isn’t as far off as I had thought…
I’ve tried showing my sadness but no one seems to get it. Anytime I have mentioned how im becoming indifferent to being alive to a friend in hopes of them actually takin interest, it’s like they think I was kidding and start playin along.
When I tried telling an older friend of mine about my concern and uncertainty of where I’m going for college in hopes of reaching out and talkig to him, he just told me how he thinks I’m a smart kid and that I will figure everything out.
How can all these people around me see a stable and happy person in me when I don’t. To people who know me, the idea of me being so confused and unhappy with life is so unrealtic to them that they think anything I say to them abot life that is solemn, uncertain, or sometimes suicidal is a joke. I just dont get how no one understands me.
I’ve stopped trying to make efforts to reach out to these people, whats the point? I will just continue putting on this fake mask that makes everyone think I’m something I’m not and try to overcome my problems alone, like I always have.