Hi Nina,
Don't get depressed, live life like never before.
Don't run or think behind thousand reasons to make you sad, but run and spend time behind one reason that you could make you happy and cheer you up.
The views you mentioned are common. Myself, being a Thal major since past 18 years of my life, I never experienced that oh god, I now no longer need to live, instead I could beg him for even more days to live because I find life around me to be beautiful.
Life is not what you think, it's how you live and that makes difference. Myself, as a child was or even a grown up wasn't ever differentiated in schools, sports activity or even other creative activities or roles and that's how I could live a life and living like a normal person.
I was diagnosed with diabetes in January 2009 too, it was an initial shock for myself, but I just laughed at it and made it a part of my life, routine. I now eat all the healthy meals that I was not eating before, and even more, and I find thal major or diabetes hasn't affected my life is any greater way.
Along with all these, I keep my family happy with laughter's and all that. We never feel that I'm a thallassemia major until the transfusion day comes, when I realize, "Oh, today is my BT day, no problem, 4 hours dedicated to you.".
Of course, I also experience fatigue sometimes (more these days) or restlessness, but I eventually overcome it.
Just do what you find happiness in and you'll see how great life is. I also take a walk in garden that is in front of my house, go in to the balcony and see the view from there and turns out how beautiful life is and what I'm missing.