Hello
First of all, I want you to read over what you wrote. You said you are 18. You have never had a girlfriend. You feel like no one outside of your family cares about you. Now it may be easy to look at those things as a negative. But you can also think about them this way:
You are only 18!! You have SO much time to find a girlfriend. Trust me, many relationships before that age are basically pointless anyways and do more harm than good

(I'm only a year older than you and I can testify to that!). You have your whole life ahead of you to find someone. Everybody's different that way; my oldest sister married her high school sweetheart at 20, my other sister only dated one guy (who ended up dying in a drunk driving incident) until she met her now-husband around the age of 29 and I've never seen her so happy. I'm kind of in the middle of the two spectrums so that probably doesn't help you any but you get my point. Everyone runs on their own little "love clock" if you will.
Second, you said you've never had a girlfriend. Again, there's time for you man! Who cares if you haven't dated or kissed yet. A lot of guys and girls have at our age but that doesn't mean it has to be that way for everyone. I have a guy friend who has never dated until he was in college and he is one of the most attractive guys I know, and an awesome person. I also have a girl friend who has never dated (for religious reasons) and she's a beautiful person, inside and out, as well. So don't think you're the only person that hasn't.
Lastly, you said no one cares about you outside of your family and you're alone in this world. Well, you say yourself your family cares

and I'm sure your psychologist cares. Don't feel like you're alone in FEELING alone either, because a lot of people (you can see from this forum even) share those feelings.
but, just wanted you to know that people care. I have no idea who you are and you don't know who I am, but I was saddened in reading your message all the same, because I want you to know people DO care and you are not alone! Keep me posted.