Hey Lightblue, I'm 23 right now, but I've felt the same way since age 15. It started the summer before my freshman year, I sort of just withdrew into myself and detatched from my emotions. No one could get a rise out of me; no laughter, no crying, no emotion, nothing.
Okay, so my Dad has always told me that with time this will all change for the better. He says that as I get older I will come out of my shell and to not worry about what life is like in high school. And he was totally right.
Once I got out of high school, I came into my own—and then I served a term in the Air Force, which was probably the best time in my life looking back. It was really fun—not saying that you should join the military, but it's definitely an option; all that life experience really helps to bring you out of your shell, and you meet lots of cool people (but of course, it is really stressful and tough at times.)
Okay but now that I am out of the military I am stuck in a rut, but I won't really go into that.
Questions for ya:
Are you into drugs a lot? What have you done besides meth? Drugs could really help your situation if you use them responsibly, but could really harm you if you use them in a stupid manner (i.e., if you use them every day, if you get addicted, if you overdose.)
Drugs that could help but aren't as harmful as meth: marijuana makes some people real giddy and happy (others it causes anxiety/depression,) benzodiazepines can help you to break out of that detatchment that you described. Cocaine used in moderation is a social drug that can help ya stomp out that detatchment. Mushrooms are a light psychedelic that I found will help ya connect to your emotions and to people, and only a small risk of sending ya over the deep edge.
That's really all I could recommend to ya. Opiates will make you out-going at first, but quickly turns to an anti-social drug that you take only to sooth yourself. Toying with psychedelics in your state of mind COULD help, but just as easily could make everything WORSE! You are only 16, so I would say wait a bit to try out drugs, but I started before age 16 so I will just say use responsibly.