1. “How valuable is an individual?”
To whom? Even the most depressed people tend to value their own lives, no matter what they may say on the subject.
2. “What makes me significant, unique, and worthy?”
This is subjective, too. It is the ability to say "I" as opposed to "you" or "it". From my point of view I mean me when I say "I".
3. What is reality?
Perception is reality. What you perceive is real to you even if no one else shares in experiencing your perception.
4. “Why do I exist?”
If you didn't exist you couldn't ask this question. You are looking for a reason why you were brought into existence. If you believe in God you probably believe that God did it to you intentionally and you want to hear someone else say it also and maybe that God loves you and has a plan for you. The trouble with that is that it misses the point. You do exist and it is up to you to find a reason to continue to exist. As they say, if you have lemons you should squeeze them for juice and add sugar and water. If you don't have sugar and water, you can slice them and arrange them in a decorative way. If you don't have a knife, peel the lemons and arrange the slices. If you don't want to ruin your fingernails peeling lemons, get someone else to do it for you or maybe sell the lemons.