what commisarbob says! Brush cleaner is amazing stuff
https://www.michaels.com/the-masters-brush-cleaner-preserver-2.5oz/10081800.htmllike this - you can get it many places not just Michael's (if one's not near you for instance) It helps clean and condition, you use it like soap basically a little goes a long way especially with our tiny brushes.
You say you're using
GW brushes? so you've rounded ones yes? Just because the regular art store ones, even when they're the right size aren't always rounds and tend to split more in my experience.
Also, you can do a little twist in the paint, before you pull the brush out and it'll help make a point.
Anyway hope that helps some!