That is Absolutely Not how meditation works. It depends on why you're meditating, whether you are concerned about the spiritual aspect or you just want to improve your life in general. Personally, I don't believe in positive affirmations. What meditating means, is that you're focusing on a single facet with all your concentration and you're trying to calm your mind in the process, so that you can think clearly, more efficiently for that particular facet; can be your problems, can be a memory you want to cherish about, can be God, can be anything. What this does, is basically, clearing your mind of all the junk and often, tangled thoughts and making it organized which often leads to, Peace, and better understanding of the situations we're in.