That happened to me too! The reason why is because you most likely skipped a lot of side quests! Go back and do the side quests, you will be grand before you know it!
It isn't strange. My Death finished the game at lvl 47 and my life at lvl 48. It is just because you didnt do all the side quests. But how I got my Life and Death to grandmaster I did Grizzleheim. It has not much progress at first but as you do the quests you see you are closer.