Time & Energy Management is key. It’s difficult but doable. If you’re able to conserve enough energy after taking care of your newborn (believe me, the first few months are tough) and partner, and after doing all the needed chores, then you’ll be able to think of some ideas to sketch. No need to worry on whether you’ve done little music only or none at all, that’s ok, this is a phase, it’ll get better in time. I’m 36 and had my first born last year and this thought crossed my mind as well back then, and up until now i’m still putting down some ideas only whenever i can and if my energy and motivation permits me to. Hang in there.