Past + Future

I always get really frustrated when people ask me a lot of questions, like "What's wrong", or "Are you okay". It's not so much the sentiment that bothers me, but rather that I feel pressured to answer, often when I would much rather not. It's hard for me to find an adequate answer that'll get off my back. "I'm fine" prompts the whole, "no your not tell me tell me tell me", while telling the truth makes them feel bad for you, and then you somehow start to feel guilty because of the way you feel, and completely unloading is even worse.
If there's something that I lie about practically every day, it's the answering the "Are you okay" question. I have never found an answer that'll make them happy, and make them leave you alone, while also not making me feel even worse.
Additionally, I'm getting tired of always feeling crappy. I'm sick most of the time, and perpetually exhausted, and I'm hurting virtually all the time. I just want to be healthy, and happy. But I cannot even remember what it's like to be happy. I'm not completely sure that I ever have felt completely happy. For as long as I can remember, I've isolated myself and found myself feeling deeply pained and hurt about... what?
Even as a little kid, I used to sit in my bedroom, away from everyone else, and think, " I really don't want to be here." and I never even identified as that being.. different? I couldn't even say what it was. I was suicidal before I even understood what death even was.
I feel like my life has been pretty much the same thing over and over again. Feeling crappy, pretending I'm fine, getting worse, breaking down completely, feeling suicidal, being pressured to "let it go" by others, and repeat.
I've never felt like people entirely understand some of the stuff I've dealt with. Certain people understand certain aspects, and are entirely oblivious to others. And I've only ever met one person who I have been able to open up to completely. The problem comes in when he started to blame me for the way I felt.
He's told me to "just stop" or insisted that I have a choice, and that I'm merely choosing to be unhappy. Maybe he never got the whole "my brain doesn't produce the chemicals that make people happy."
I've heard the whole "things get better" innumerable times. But I cannot see any light at the end of the tunnel. All I know is that some days are better than others, but it feels like I'm always going to be on the brink. I've been in this bloody tunnel as long as I can remember, and I see no future for myself. I try to picture it-- in a relationship, going to school, functioning as a normal person, etc. But try as I may, my future is a small future, and none of those happy, normal things are for me.
I'm guessing that I am stuck with this shit tunnel for the rest of my life, however much longer that may be. I know that I will always be on meds, I will always be depressed, and I will always feel alone.