My first two children were like that - they were fantastic sleepers as newborns but around 3 months they started waking very frequently. DS woke every hour from 3-8 months old. DD slightly less. Now my third baby is a great sleeper. I have done nothing differently with them and I honestly believe that it is not a parenting issue but just how they are so please don't beat yourself up over something that is most likely not your fault at all.

Forget what the books say - if dummy and wrapping help then keep going with it. He will outgrow it eventually.

I don't really have any advice because I have been there a couple of times myself and couldn't find any solutions that worked for us. I did have them in the bed with me so I could feed them back to sleep without having to get up which did help me to function.

I agree with the idea of getting a bit of help so you can have a catch up nap during the day. Can your DH/mum/MIL/friend take the kids for a walk while you have a snooze? I know how exhausting it can be xx