I'm going to high school and I have social anxiety...

I'm going into high school this year and I'm very nervous. I haven't been clinically diagnosed with social anxiety disorder, but I definetly show all the symptoms. I would just like to hear from any of your experiences and any encouragement or advice will help a lot. Iv'e always been very shy, but it has really begun to negatively impact my life since the beginning of this year. Since I consider myself an introvert and think I have this disorder, I'm really not that interested in forming friendships. I avoid any potential social situation and get very nervous before and during one. This is quite embarrasing and it only fuels my fear, but I begin to sweat a lot, tremble, my mind just goes blank, my heart races, I start hyperventalating, and/or I feel lightheaded and naseau. Sometimes I even have headaches. Every. Single. Day. Especially at school, it's a complete nightmare. I hate eating, drinking, writing, or doing almost anything while being around people and especially while being observed. My mind just goes blank and I just sit/stand there paralyzed. I'm worried that I might even faint when I have to do my two presentations or go on stage for promotion. I'm so worried and I have a hard time falling asleep. I bet at this point, you would tell me to just chill. It's not that easy, though. And now, I'm going to add the cherry on top of that anxiety and stress. I just suppress all these emotions at home so that my mom doesn't suspect and pretend to be happy and smile when I feel like I'm dying from the inside. Ever since she's found out iv'e been more anxious than usual, she's pointed it every single little thing about me that shows distress and tells me to just calm down. I see that she's trying to help, but she's not really understanding either. She tells me that she was often stressed out at my age, but she's always asking me why I'm so anxious around people. I sometimes think that she made me the social wreck I am because she would make fun of me. I was a very sensitive bean at a young age and I still am. I know she's only joking when she says I sound like a mouse or imitates me looking down at the floor like a deppresed person, but it really hurts on the inside. And sometimes, my little sister joins in the making fun of me. Iv'e begun to think other people think of me like this and may have become very shy because of that. I just needed to let all of this emotion out. I've become so used to hiding my true colors and feelings around people (whom I'm around at all times), that i'm starting to forget who I am and see no connection to the person I see on the mirror. I feel like i'm losing my ability to feel emotions and I'm just living inside a body just observing, feeling so automatic. Iv'e begun to wonder about many deep and dark things and I hate myself now. Idk, if you could maybe share your own experiences or possibly give me advice, that would be very helpful. Thank you for taking the time the read this, I did not expect you to listen to another stranger's problems.