I think most people here will tell you to seek a therapist who you can build trust with. A person who is a third party helper, so to speak. You know, you give them money to not judge you and all that.
There is other advice. Journaling. Building a support network. Etc. The internet can help. It is an anonymous world and bare your soul to people within a somewhat controlled environment. I call this stranger therapy.
There are many things I will say here.
1.) Building walls cannot protect you from yourself. Therefor in the grand scheme it doesn't necessarily protect you from pain. I don't know about you but I can be a real jerk to myself. 2.) You said that you haven't had relationships. It sounds like you have, just not the ones you need or want. 3.) Relationships need both parties to risk themselves, to trust, to love (to a certain extent) and to be functional. This is a sort of cultivation. It's that whole "you reap what you sow" mumbo jumbo. 4.) Love yourself. I think that's the most important thing. When you love yourself. You learn to recognize when others are loving you. You learn what love is all about. Love your imperfections and all of the things that come with you. Because, it will allow the cultivation of love.
Something that has helped me in life is understanding that all anger is basically the lack of acceptance. To get past anger (or at least not repress it), the best thing is to accept the situation for what it is and move on to bigger brighter things. Easier said than done. I know.
I can't completely understand your family situation as I am not a part of it. However, one of my best friends is Indian and I have supported her though out the years. (Amongst other things, she has the paler more successful and married older sister. ) It allows me some cultural sympathizing.
If you ever want to talk to someone. Send me a message. I'll listen and respond. It might not always be what you want to hear. I can be blunt at times. However, it would always be honest and with the caring nurture from one kind hearted human to another.
When we talk about helping humanity, we tend to forget about our intrinsic interdependence. We have this idea that there is a great separation between you and me and the billions of others that live on this planet. Yet, we share everything.
Think about the complexity of the Internet, all the people involved with creating that. From the computers we use to access the Internet to the people who created them. How many lives were touched by the act of creating a single computer?
We are truly connected. I believe that this idea of separation is what can really make a person feel like anything they do, isn't as important as it actually is. Every moment you smile, that small act can put each person you smile at in a slightly better mood. Thereby slightly improving the lives of each person in which that person encounters.
This is an example of how doing even the smallest thing can change the world.
When you talk about humanity, you could mean human rights, poverty, food stability, etc. If any of those things are your passion, then do research. See how you can help. Sign petitions. Bring things like tooth brushes and soap to shelters. Find out what the food banks would need. Etc
If you want more ideas, then let's start a dialog.
Remember the moment you want to make a change for the better, you are creating the environment to do so.