Both children will not sleep alone!!

I have a 4 year old daughter and a 10 month old son. Daughter was pretty good at sleep at night by 6 months was in her cot and woke for milk went back down, did around a year of sleeping through then around 2 she switched and i started co-sleeping as we weren’t getting sleep another way. Since then she will not sleep alone. Cue baby boy coming along - he slept brilliantly for the first 8 weeks then had reflux so slept badly untill we resolved it, he was still in his next to me at 8 months and was doing okay through the night few wake ups but would settle but then around 8.5 months he just started waking every hour wouldn’t settles unless held he didn’t want milk didn’t want to be awake just wanted to be held as soon as I held him he would go straight back to sleep. He’s not 10 months and we finally made the decision to move him into his big cot and my god he’s awake every hour. Again still doesn’t wasn’t milk, we do a good bed time routine bath, book, bottle bed. He’s plenty warm enough but he will not stay in his cot. Soon as I hold him he’s straight to sleep and I don’t hear from him. So now I’m co-sleeping with both just to be able to function otherwise it would not be safe to drive or leave the house. How can they both need me so much apart from older one going to preschool which she loves I am with them 24/7 don’t go out, I work from home or with them. So I’m just at a point where I’m wondering what I’ve done wrong, what I do next. I love them and love they need me but I need them to sleep! 😴 One very tired mummy!