Grumpy 9 month old, changed over night 😩

My boy is 9 and a half months old and since he turned 8 months he has changed over night, he is super clingy and wines all day. Its so draining, I can’t put him down to do anything without him crying. He does this with anybody he is with and not just me. He’s the same at nursery, with grandparents and dad. I know separation anxiety is a huge thing right now but I just can’t see it getting any easier. Nursery ring me and tell me he’s constantly crying and it’s so hard to focus at work whilst I know he’s like this. I did put it down to teething as he had all 4 top teeth come through at once but now they’ve come through he is still the same. He’s been like this for nearly 2 months. Any tips please??