A partner isn't going to make you feel not alone in the long term.
These feelings hommefatal, won't go away all at once, simply because it takes time to develop confidence and a sense of who you are. I think most of us at 15 were not quite comfortable with ourselves. One way of dealing with that is trying on different personas and different ways of dressing to see if they fit and feel comfortable. Most people do that in some way or another.
Your "acting like a lunatic" I think is one way of trying on a different persona. In this case, it is a particularly obnoxious one that people sometimes don't react well to. The pity is that people never actually get to meet you, which you are not sure that they'll like. If you act loud and a little offensive, then it is not nearly so devastating if they don't like you, because it's not really you.
You also have a real need to be unique. The rest of us all want to be appreciated for what makes us different from other people. However, there are ways to go about it which alienate others, and ways that will bring others closer to us. It looks to me that if given the choice, for you negative attention (even if it hurts you) is much better than no attention at all.
The biggest two keys dealing with the uncomfortable and frightening feelings you mentioned are these: first of all, you need a close emotional connection to someone that will love you unconditionally. If you don't have this at home, you need to find it in the form of a teacher, someone at a church, or a caring adult in the community. Although people your own age aren't bad, they are going through the same struggles as you are and do not have abililty at this time to give you the attention and love that you need in a healthy way. When your brain is less busy trying to find a strong attachment to someone, it is will start helping you develop emotionally. There is a bunch more that could be said about this, but I will save for another post. Secondly, you need to develop a sense of identity and confidence based on actual skills as well as character qualities that you develop. In every conversation and with every person you meet, there is something that you can learn from them. Even people who do things negatively are opportunities to learn how you don't want to go about it. Start reaching out to the people that you meet. Ask them questions. Build on the things that you are already good at. Volunteer. Teach other people any skills you have and keep acquiring new ones. Think of ways that you could show appreciation or help for others. You will find that people start responding differently to you and you will also have confidence from knowing that you know how to do something well and have something to offer others. There is only a need to act crazy and unconventional (and offensive) when you don't feel like you have a legitimate identity to show to those that you meet. I think there is an interesting and talented person in you that others rarely get to look at when they meet you. Find him!!