First of all, I don't think there is such a thing as "normal". It's just a word for people who fall into society's often narrow conception of how we should just blindly conform to social norms. I find a few things I've learned in my years of studying experimental psych. Some studies have shown that people who are experiencing depression are seeing "reality" more so than those who are optimistic. Depression during our evolutionary history was adaptive at one point or we wouldn't be alive today. Depression has also been found to be actually helpful in some professions, e.g. professors, artists, etc. If society's perception was turned on it's head, maybe we could even say that people who aren't struggling with depression are to some extent "delusional". It's just an interesting and different way to look at something that is often just seen negatively. Of course, those people who are on the spectrum of being extremely pessamistic and/or depressed are seeing things in a distorted way. I have struggled with depression for years. I've found that reframing things and accepting how my life is now, good and bad, has helped me the most.