Go without any plans, any future, just go and see what happens. You'll be free. It may be dangerous, you might not make it, but if your other choice was death the day before, then everything now is just gravy anyways. Don't worry about it.
This may sound silly and simple and extreme, but if you _are_ at that stage then this should be your stop gap. From now on when you're in that dark spot just think about when you're going to pull the trigger on this, not on yourself.
Of course there are lots of things you can do before it comes to this, but if you're past that, just leave your current life totally.
It sounds like a good start to a story, but bad real-world advice.
I had an ex-gf who worked on a suicide hotline, and apparently one of the most powerful things they had in their arsenal were questions like "Who do you think would find your body?" and "How do you think it would affect them?" and other encouragements for suicidal person to think about how their suicide would affect those around them. If you're backpacking alone in Africa, having taken your leave from everybody in your life two months ago, it seems like there'd be a lot less to keep you.
(Also, no offence, but I'm disinclined to take suicide-prevention advice from anyone named "necro"...)
I sincerely doubt it would make any difference, largely because of how you feel about life + yourself (it would require an acceptance of capability of doing such things) + the point of trying to help such a horrid world. I think the more immediate consideration of those people finding your body, etc. will be more effective as that's something undeniable and forces you to consider others in a non-fanciful way.
In other words, a lot of the time the things that are making you unhappy are internal: lack of confidence, self-esteem, self respect, or non-functional brain chemistry. Sure, if there's something weighing you down (a bad relationship or job) then change it. But if you're unhappy with everything in your life then what you need to change is yourself.
The experience of clinical depression is so unutterably horrible that unless you've experienced it you can't know what it's like. There is a huge gulf between moderate depression and the clinical variety. In the depths of serious depression you barely have the energy to get out of bed let alone help anybody, and suggesting that somebody ought to give up aspirations to help these poor, helpless Africans (which country in Africa I might ask - I think natives of African nations might take offence here) is actually more likely to inspire feelings of guilt and isolation than a sense of hope.
The best solution for somebody experiencing issues is to seek professional guidance and not take romanticised + frankly fanciful advice from a random person on a news site.
Sorry to be harsh, but this could affect somebody out there and I think it needs to be said.
Of course it's different for everyone, but it's easy to say "Sell your possessions and go forth" - not everyone can do it though, being not willing or able.
The feeling can be beyond words and the energy needed to talk about it seems beyond us but I've gone the pretend route where you put on a brave face and act like a different person and it's just not healthy. It leads to you being even more depressed and no one having a clue which is so dangerous. I don't have the answers to getting over it (which I have done, personally) but I do know that acting like a different person isn't a good way to go. I hope you're better these days, feel free to get in touch if not. I'd be happy to talk about whatever.