OP, your predicament reminds me of a situation that I and my coworkers are having with a certain person at work. We all eat lunch together in the company lunchroom, and one day, one of the kind-hearted souls decided she felt sorry for this woman eating all by herself, so she invited her to our table.
Big mistake. This person now sits with us every single day and not only has no sense of personal space, but she goes on and on and on about the same stories and subjects over and over again. If you do try to carry on a conversation with her, you get the sense that she is not really listening, but just waiting for you to stop talking so that she can share her oh-so amusing anecdote. She does not recognize the signs and social cues from the rest of us that her story has gone on too long or we are not interested or bored or uncomfortable or would really like to talk to the other people in the group who are not so irritating.
I am not surprised that the teacher wasn’t able to get into a lot of specifics as to what you are doing “wrong”, because most of my coworker’s offenses really don’t sound that bad to people who don’t know her, and it is actually hard for me to put a finger on what exactly is so irritating. A lot of people talk about, for instance, their families or their vehicles, and it is mildly interesting small talk. She talks about these things, going on and on and on with uninteresting detail, and it drives me up the wall.
This has been a sign of consternation to the rest of us, because while going to a supervisor or HR seems like way overkill, especially since this is technically not work time, it has really cut down on the enjoyment at what should be a pleasant time of day. We’ve even told her to shut up, but it was kind of in a joking matter, so she thinks it’s a joke. Part of the problem lies with us, because in Minnesota culture, direct confrontation is very rude, so we rely so much on these social cues that she just can’t read. I think the solution will ultimately have to be direct confrontation, but that could open us up to trouble. What if she goes to HR on us as a result?
My point is, OP, if you recognize anything about yourself in my story, please understand that your classmates and teacher are not being mean, and even if other people seem to get just as close or talk about the same subjects, the way you do it makes others uncomfortable or irritated. In the short term, I would suggest stopping any of the behaviors that you even think might be causing discomfort immediately. In the long term, if you think that the problem is that you are not recognizing others’ social cues, you may want to see if there is some sort of therapy available out there, because, believe me, you do not want to be in your 40’s and having this sort of problem in your work life.