thank you for the replies!

yep DH and I are not comfortable with either of their suggestions. it didnt feel right to us to either drug him up or let him kick and scream himself to sleep!

we have ducted gas heating in our house but cant use it overngiht as its so loud it would wake DS up. we just got an column heater and started using that in DS's room to warm his room up a bit. we thought it might be the mattress on the toddler bed making him uncomfortable so i put a blanket between the sheet and mattress last night to see if that helped. he still came into us but managed to sleep for 5 hours between being put back to bed and coming back into us.