depression

Lol diseases still have underlying causes. "What is making you have mono?" Could be the fact that the person you've been hooking up with had mono.
"What is making you depressed?" Lots of things could be contributing to your depression, like body image issues, eating disorders, sleep disorders, etc..

Shaming people for asking these questions is ignorant and counter-productive.

I don't know how I'm going to go forward in my career as I don't like any of these roles to do. Not only that most girls have been cool with me and a lot have wanted to go out with me, so when I got hooked on a girl that was interested but said no to going out, I got very crushed inside and I don't see how I can ever get back and even be with another girl again.

Things just seem very glum and work either seems robotic, meaningless, boring, or tough to make money from.

Things used to be good and now I feel like despite all the work I put into everything things are bleak in finding something I love in a career and then with girls it feels like I just get played like a YoYo, even though things work out well a lot of the times with girls for me. Let alone I'm already old like 21, and lived a quarter of my life, and the meaning of doing some s-it job forever has got me depressed, and pretending I enjoy it, and going through the constant getting played by women, and all the other BS, makes it very hard to see any light in the remaining 60 years of my life.

Again, I will find answers, and no matter what will do my best, but damn is it depressing. Am I going to find another girl to be with only to be let down in a few months? Am I going to have to waste my talent in some crap job till my life is over? Life seems to just be a crappy mess of negatives, where deep sadness can only pervade from my core when there is just a superficial mess of things in life.