School and social anxiety

Hi, everyone who is reading. Well to start off, I'm a sophomore in high school and since the beginning of the school year I've felt as if I've pushed myself too far this year because I'm talking class that are way above my grade level. I'm taking these classes so I can start setting up for academic scholarships but this year turned out to be super hard. I lucked out last grading period with a really low C in a class and a low A in another but this grading period I'm already starting off with F's and I can't have that bring down my GPA. I don't know if I'm going to be able to apply for the scholarship I need now and I get that it's only my sophomore year but every grade counts and I don't want to have to take out student loans and be in debt. I usually don't do this bad but I don't know how to cope with it. I feel stupid. Then next year my mom wants me to go into a program that turns all my classes into AP classes (college level courses) and I really don't know if I can do it.
Secondly, I can't talk to people. Every time I try to have a conversation I shut down because I feel like I'm going to say the wrong thing. I don't want to drive them away because of something I joke around about and they take offense to. That and I just get really nervous around people in general. When someone talks to me I start to shiver uncontrollably and studder. I sometimes want to talk to that person and it still happens. I'm even nervous to send this message. I just kinda melt and brake down in those situations and I hate myself for it but I can't do anything about it.
Im sorry, thank you for reading