HELP! THIS IS NOT MAGIC!!!!!!!!!!!!!!!!!!!!!!!!!…

ok, i have a spacer in my back bottom right tooth. one day i see a tooth holding one end in plave, a big strong tooth,,,, but today, i see an itty bitty point where the big strong tooth WAS. i would know if i lost a tooth. i can't pull it out cuz my gums grew over the back of it. why on earth did this happen and what do i need to do?