Does it sound like I have Social anxiety disorder?

I'm 14 and 'm terrified of socializing, i worry about social events like parties weeks before they actually happen, and when they do i just clam up, my heart beats really fast, i get heart palpitations, i feel faint and sick quite a lot of the time when socializing, i can't make eye contact, i start shaking and i stutter when i speak. I'm really scared of what people will be thinking, and what they will think if they notice i'm nervous, i'm fine around family members i live with, but everybody else i'm really scared of, it's not a phobia of going outside, it's just socializing really.. because of this, i'm really depressed, i have no confidence, low self esteem.. and i don't leave the house very often, but it's not because im scared of going outside, it's the people that are outside.. do you think i have Social anxiety disorder? what should i do? if i don't have Social anxiety disorder.. what do i have? :( is this normal for a 14 year old? i don't think it is, when ever i see teenagers in the street their social lives are flourishing :( help me