Dear Wandering Soul~
I am sorry to hear you felt so low you tried to kill yourself, I have been there too and you are right, your life is worth more than you can possibly appreciate when so depressed by circumstances.
It only takes a small change to turn your life around. The smallest and most significant is the ability to cope with the horrible events life throws at you.
May I ask if you feel that way now? (I am good now, I was not before.)
If the feeling is there now or returns in the future please take the time to contact the Suicide Call Back Service (1300 659 467) who I find are exceptional. They use qualified professionals, are compassionate understanding and realistic. You can contact them more than once without having to explain everything each time. If they are busy and you cannot hang on then use Lifeline (13 11 14). They are OK
The words of another human being are a comfort.
May I suggest you do not give up on volunteering, and perhaps attempt to try in person as Birdy suggests may work better. It is possible your own culture may be an asset, perhaps at a local Migrant Center, a museum which holds material from your country of origin, an organization such as the Department of Heath may wish to publish material in your native tongue.Your imagination can be used here to think of opportunities.
Take your time and then approach such places and explain you are an assset -which you are.
I stress volunteering for a couple of reasons. If you can find something it gives purpose and structure to your life, hopefully satisfaction and accomplishment too. Also often it is a pathway to a paid job.
This has been my personal experience.
I am sure that smile meant a lot - to both of you
you did say
I still want to make a difference to this broken world. Make myself count. A better human. I smiled at a homeless person today.
There are many good people that respond to people like you with your philosophy, it is a matter of being recognized at the right moment.