Help my hair is f*cked!!! 😭

So ever since I got pregnant with my second my scalp has been flaky 😒 well I started using head and shoulders and it helped a little bit, I still couldn’t wear my hair down like I used to though, anyway fast faward now pregnant with my 3rd and it seems to be 10 times worse it’s so depressing! Iv tried dandruff shampoos, tea tree ones and nothing seems to be working. It’s like as soon as I just slightly scratch my scalp it starts to flake. So fed up with having to hide it in a pony tail all the time. I want to start having it down and looking nice like I used to be able to before I had kids 😤😭😭 anyone had similar experience or might know what it could be? I’m definitely washing the shampoo out properly coz I spend ages washing it out in hopes it could be that 🤦🏻‍♀️ what can I use to stop this!!? Thanks!