Would it make sense to have a meeting with the owner and your manager? Since the manager did not seems to have problems with your work, perhaps you can all come to a middle ground someplace. Give the opportunity for discussion, improvement and also it is a conversation that includes 3 people so that there is no margin for changing the story or "misunderstanding". In the meantime, yes, you can look for a new job when you are not at work. Not a bad idea.