Sorry, i know this doesnt exactly deserve its own topic, but i spent ages looking around last night, and asking people but i couldnt find an answer

I was in an XP Lobby on Black Ops 2 last night, and i hit level 55, i still needed a good 50,000xp to hit prestige, but when i joined the lobby again, it said, 'already max level' and kicked me, with no XP, do i actually have to gain the rest of level 55 legit, or is there a way around it?