DS 19 months has always slept well once asleep but we have often struggled to get him off to sleep. This however hasn't been a problem for several months until this week. Not really sure what has changed but he has just had screaming tantrums at nap and bed time. Tonight went on for almost 2 hours of me sitting in his room, holding him and talking to him until he eventually gave up and went to sleep. It was horrible to see him in such a state. 
I try to parent in a HTTSOKWL/UP type way but am at a loss as to how to calm him down. I used to just pick him up and sit in a chair in his room with him until he fell asleep and then put him back in his cot but I don't really want to get back into this habit as he then used to wake up as soon as I put him down and then I had to start all over again!
Sorry for the long post, hopefully someone will have some ideas.