>my first crush was a guy who turned out to have depression, anxiety and narcissism but he was good at hiding it
Many people, especially those early in relationships tend to wear masks to hide their own personal issues and insecurities. From your response it sounds like you naturally perceive them for who they are, but also are naturally attracted to personalities like this.
>we stay friends, the quality is really weird, sometimes great and sometimes horrible
Let's go further here. What is the nature of your friendships? Are they simply platonic and friendly, or do you find yourself intent on helping them through their issues? Do you want to be "there" for them at all times?
>most often they do but they don't want to build a relationship because they think they are too fucked up or they show some signs of interest but stifle the if it makes sense and push me away when I try to initiate
A lot of people who have checkered pasts are hesitant to start relationships because they are chained to previous failures. If you are as giving and nurturing as you claim, then that would only intensify such a reaction. Those with clinical depression likely too would not want to subject you to days and days of barely getting out of bed.
>I would say that I'm quiet and introverted, into art and literature, caring and emotional, I like helping people and nature and fixing things.
You sound like a sweet girl, but there is a point where you can become too giving of yourself, especially for those who aren't going to change. When dealing with any mental health issue, the most you can do is provide an environment and resources for the person to make good choices. You cannot choose for them.
I don't know what you do for your job or age for that matter, but you might want to look into the caring professions like social work which seems to support your nature. Did you only come to Jow Forums for advice, or are you surveying other online locales?