So I audition for college this saturday, everything was going good I was confident and I was ready and then all of the sudden out of no where I start missing pitches I can barely hit notes and its becoming harder to even play in the middle register of my horn the only thing I can play comfortably is low notes, I was playing my audition piece morceau de concert nicely 2 weeks ago and now i can barely get pass the first 4 measures can anybody help me please I don't know what to do.

Perhaps you've exhausted your lip muscles. They'll need to rest. Low notes will be OK but keep away from the high register completely for a day or so. Make sure you do a good warm-up before contemplating higher notes and don't stress your lips. Try taking a long break (30 minutes) between warming up and playing.

I hope everything goes well on Saturday. Let air flow make your lips vibrate faster rather than stretching you lips.

thanks for your help any more suggestions.

I know this is kinda late but I had a similar experience while preparing for an audition for the Eugene Symphony. One week before the audition I couldn't play at all. I was missing stuff I never missed and had real trouble with response. It turns out I was extremely dehydrated. I drank a whole bunch of water that day and by the next day I felt fine. I have found that regular hydration is the best way of making my lips feel the same day in and day out.