My 11 month old won’t go to sleep!? 😩

So my 11 month old (soon to be 1 in 13days!!?) recently hates going to bed at night like screams when we put him down in his cot.. he’s normally so easy to put to bed and used to sleep 7pm-7am but for the last week he screams and cries and then at about 11/12pm at night he wakes up crying and screaming and takes about 2 hours to get back to sleep and I end up having to put my hand on his back and stay in the room till he is asleep.. it’s sooo unlike him! And I just don’t understand why nothing has change, his routine is the exact same..

Please someone help me I feel like a useless mum right now because just seems like he wants a me and wants to cuddle me 😢😢