I know it's rubbish right now, but this is biologically normal! Nothing wrong, even though it's difficult for you! Just keep trying, keep doing different things. They change daily so if you've had a bad day just try to remember tomorrow will be different and nothing is permanent x
I’m sure at this age their maternal melatonin wares off and they begin making their own. That’s why sleep is so hard at this age for some! It will get better and you’re doing nothing wrong ❤️