"Statistically speaking it's very unlikely for one's quality of life to decrease or increate throughout your life"
It's something one of my profs told me to cheer me up when I was feeling down and came in his office to talk about some theorems. It makes perfect sense, that could be the reason why the middle class is the largest in most countries, despite the fact that people with lower income tend to reproduce more often and why the upper class doesn't have almost any newcomers.

If you're going through shit times, just know that there is math to back up that you'll be facing better times soon.