Many people live daily knowing their dreams will never come true. Actually most people never fulfill their dreams. What they do is work to make the best of whatever life hands them. That means finding joy and contentment in their work, hobbies, religion, friends, music, volunteer work or whatever they find meaningful. That means different things to every person.
It does sound like you may be a bit depressed though, so you need to speak with a licensed mental health counselor. He or she can help you develop coping skills for when you are down and think you will never be happy again. You might also speak to your religious leader if you are part of a faith community.
Please let me know what I can do to help.