6th grade isn’t bad. You just have to get used to the new environment. 6th grade was actually really fun for me (except for when I slammed my foot against the wall) since you have social anxiety (like me) I suggest staying in a friend group or with a close friend for lunch and pe. I really only talk to my friend group during lunch and pe unless I absolutely have to talk to someone else.
6th grade is pretty fun and you might find some new people to talk to since I assume you are going to a new school. (6th grade was still apart of elementary school for me)