Worry about things you cannot change is wasted effort.
The world is not perfect, but it never was... and it never will be.
You think you have it bad, our Lord and Savior had to live daily knowing he would be betrayed by one of his closest friends and confidants, that he would be publicly tortured and humiliated... baked bleeding in the hot sun nailed to a cross and die a horrible death.
If you biggest worries in life are the issues of grand geopolitical issues such as war and poverty and such, you are damnedably lucky. Instead of focusing on the evil of the world... Evil that will exist until the end time... nothing you and I do can stop it from existing... focus on the good.
There is good in the world.. lots of it. Yes, you won't find much of it on the evening news, or in the paper, or even in much of popular entertainment these days... after all our abherantly stained souls are much more easily facinated by a slaughter of 1 man by evil, than the thousands of good works that happen every day quietly.
If you doubt this world is good, then only go find a nice forest or woods to walk through... a state or national park if you don't have any private land you can walk.... Go out there, take some water, maybe a walking stick, and a compass and map if you don't know the area well... and start walking... and keep walking until you see and hear the world that is... not the world that is being fed to you by others.
If you need to find purpose, then find those that help others... your local church or community groups.... and get involved. You don't need to be an evangelical to do God's will or God's work, heck you don't even have to be all that holy.. just be who you are, and bring what you have to the table. Remember, some of the worlds greatest saints were first some of the worlds greatest sinners.
You do these things and you will come to find that the world is indeed so beautiful, and so good, that we take it for granted... we don't even notice it when it is right in front of our eyes because it is so common and so pleantiful.
Do not dispare, and do not fear.. God does love you, and he cares for you.... even if you "both know you are the problem"... After all, he knows that even with our best efforts...we all are... after all, he doesn't make mistakes.
All good things in this world come from God, he only lets us use them for a little while.... so use them, all of them, to make things better in whatever way you can...
I cannot walk a mile in your shoes, you cannot walk a mile in mine.. but someone walks every mile in both our shoes.. so don't be afraid to confer with him.. he knows the path you have walked. Every step, every stumble, every summit and valley, he was there and will be there. Whatever past things bring you shame, do not dwell on them... he will forgive you if you only ask. You must also be able to forgive yourself.
If you stumble, you are human... do not dwell on them, work to not repeat them... but never did a man walk a journey of any distance where he did not stumble, and never at the end of that road were the stumbles what defined his reward.
Your advice is well suited for everyone.
Yeah, sure buddy, I'll do just that... I'll keep walking until no one can hear me scream... and then a darn bear will come out of the brush and have me for lunch!