My LO is 10months old and has always been a very good sleeper sleeping 11-12hours solidly through the night from around 8/10 weeks of age. He has always sent himself off to sleep with me lying him in his cot awake, giving him his label blanket and he would be asleep withing 5-10 minutes.
Suddenly over the last two weeks he screams and cries as soon as we go into his bedroom. I lie him down and he get straight back up standing, screaming and crying in the cot. I have tried to leave him and stood outside the door but he got so upset I haven’t done this again since 
Tonight he got so upset once I put him in the cot that he cried until he was sick. This was even after I’d picked him out of the cot and tried soothing him and rocking him in my arms. He is definitely tired as he is almost falling asleep from exhaustion.
Has anyone else had anything like this? I’m really hoping it’s just a phase as I hate to see him so upset and he is getting himself very worked up.
Any advice would be much appreciated
sorry for the long post!!