Haha, I'm a weirdo Goth! Muhahahahaha! Boo!

Anyway, to answer:
Only you can really know if you're transsexual, and talking with a counselor might also help you discover if you are or not. -- sorry of that sound cliche, but it's true.
Also, you might also fit under other parts of the transgender umbrella, like you could be a cross-dresser, for instance. (Nothing wrong with that)
I should also mention that being a girl isn't easy, especially being a woman in transition. It's not a magical fix and transitioning doesn't equal instant popularity. It's a difficult road, and you can find that you'll be just as lonely as before. I'm not trying to scare you, but only tell you how it is.
Take a look at some other posts and see what people go through with transition. It's not easy. But we do it because that's who we are, and we get to the point of willing to give up everything -- careers, friends, family -- to be who we are. It's tough, but it's also rewarding in another way 'cause you're becoming who you are.
I think going to a counselor can help you, not only for the transgender thing but also for other things going on in your world. The depression, for example.
I'm a strong believer that working on other issues helps you transition better, and be prepared to go through with it. Especially if you have depression.
Also, even after you transition, it doesn't mean that life will get any easier, that you won't have depression, and that you'll get lots of friends. It's still a difficult road. A woman's world isn't easy.
As for myself, I still get depression. I'm bipolar. Transition didn't fix that. I still have to take meds for that. I pulled all of my effort to be social and to have friends, even before I started to transition. I worked hard at it, 'cause I knew that having good, understanding friends would be a great asset to help me on my journey. I lost many family members, who now count me as dead and haven't talked to me in over 3 years.
But, on the positive side I'm more happier and confident over all because I am who I am, a woman, and I know that. I also think working hard my psychological problems helped me over all, and especially helped with my transition. It was a lot of work, but very rewarding mentally and socially.
Today, I'm a woman. I know who I am. I have lots of friends and enjoy a lot of activities. Life is great. I still have my ups and downs, and I still see my psychiatrist. But, over all, I know that I'm where I'm supposed to be.
Transition, you see, is a lot more than just "becoming a woman," getting surgery (SRS/Sex Reassignment Surgery FFS/Facial Feminaiztion Surgery), taking hormones to change your body, and so on --- there's psychological aspects and social aspects as well.
But, even all beyond that, transition is essentially being who you are. That's is the very core of it all. All of the rest, the HRT (Hormones), surgeries, psychological, and social aspects... those are only tools to assist you, not the end-all-of-be-all. It's about being
you! Make Sense?
So, work on that. Work on being yourself, not becoming something, just be you. Do a lot of soul searching. See a counceller to work out your depression issues and any other issues you might have. You might be trans, or maybe not. What's most important is that you work on being who you are, and go from there.
I like to think of transition is a journey to self.
Good luck!
--Natalie