How do you get over anger , resentment at the modern world?

I can understand your feelings to a point, but your idea that pretty much everyone else is happy is really over the top. There are few of us who have escaped hard times. There are few of us who haven't been unemployed, ill, suffered a crisis in our family, etc. We can't choose the things that happen to us, but we can choose how we react to them. You should get involved in helping others because that may help you to understand there are many worse off than you are who still manage to keep moving and not have such resentment. You can do it. It's up to you. It's your choice.