Lots of people who are far worse off than you probably want to give up every single day.
Somehow they find the will to see past the curtain, and some even have an opportunity to make the changes that will improve their lives. Many live in abject poverty, with no way out, and they carry on. Hundreds of families who live in a Guatemalan dump, scavenging other people's garbage to eke out meager livings. The children still laugh, and play, and mothers still live their lives for their children.
Step back, look at what you have. Recognize that you alone hold the key to yourself.
And like others have said, seek professional help. I know people who are stricken with anxiety and depression, and have come close to suicide. But with a combination of therapy, drugs, and talking with people who help them focus on the positive, they live much better lives, and see some light in their worlds.
That world is outside, and it is inside.