Well I go to an alternative school because I'm not good with dealing with huge classes and crowded schools (again, introversion), and my current school doesn't serve lunch or have lunch tables. You're supposed to go out to eat, so I usually just walk to one of the restaurants around my school and chill there for the hour until lunch is over, but I am usually eating with this guy named Cody. So technically, no I do not sit alone during lunch, but when I was at my other school I did. I actually only had one friend in the whole school and I didn't have any classes with her, so I was alone most of the day anyways. I don't know how your school works, but if it's anything like my old school, you could probably find an empty spot a chair or two away from someone you don't know. That's what I did. Also you could maybe (again, I don't know how your school works. We could do this in my old school) go to the library during lunch and read or get on the computers or something.