No, it is not the time to panic. You are worried over what people are saying and not what you have experienced. You need to find out the lay of the land yourself.
Don't do it. I know your excited and proud about the master's degree, as you should be. Just do a Google search for post-nomials and master's degree. The consensus seems to be that those who use them are insecure. I've even seen people use them for certifications and that seems desperate.