I planned a vacation and before I put my request in my boss announced that he would not be allowing any time?

off for the next few months. Our normal policy is to request the time off 2 weeks in advance and I have plenty of time to comply with that guideline. My company does restrict certain days due to business reasons and seasonality but this is not at that time. I have paid for my trip in full and my travel companions have worked their schedules to allow them to go. I am owed plenty of time off and seldom take a vacation. How should I approach this with my boss? I really need this vacation.