2.5 year old suddenly won’t sleep

K

my son has always been a perfect sleeper. slept all night, in his own room, always fell asleep on his own as soon as he was placed in his crib, etc. but starting around a week ago he has absolutely refused his crib. the minute we step foot in his room he starts screaming and crying. wont lay down, just stands in his crib holding his sippy while scream crying until either his dad or i bring him in our room. he’s always been an amazing sleeper unless he’s sick. is this a regression? teething? i thought maybe something in his room was scaring him so took out some pictures and stuffed animals we had on a shelf but that didn’t work either. we’re up until 2am or later most nights now. not sure what to do :/ i don’t want to make falling asleep in our bed a habit. and i absolutely refuse cio