Parenting a Pre-teen

Today my son's teacher requested a conference.  She said she was requesting the conference on behalf of all of my son's teachers.  Last week, my son brought home a progress report that showed he was not passing social studies.  I emailed the teacher and she replied that his behavior had been disrespectful and he was missing several assignments.  She copied several other people on the email, some of which I had never heard of.  I spoke with my son who promised to mend his ways, and the report from his teacher was good, but then he apparently made some crude jokes a few days later, and I received the request mentioned above.  This time there were about 10 other people copied on the email.  I know my son.  He is struggling to find the line between who we are raising him to be and who it is that makes his friends laugh and helps him find peer acceptance.  He is not very wise in this department.  I am having trouble keeping up with his newly flowing hormones, but now I am also finding myself unable to keep up with his teacher who seems to be going full tilt into labeling him a problem student.  So I find myself on the defensive; a mama bear protecting her cub.  I'm a bit at a loss as to how to proceed.  I'm sure my son is far from being a model student, but I also think this teacher is overreacting and blowing it out of proportion.