dont worry, plenty of us know the feeling
i had to do a presentation with someone who was so stupid that he literally read the slides word for word, if the lecturer had not been so sympathetic to our cause since he's the one who stuck us with the idiot, he would have single handedly bombed our mark instead of just his
moral of the story - group work sucks regardless of who picks the group, especially when it can effect something as important and long term as a grade