being a mummy is tough

K8
My baby was 4 weeks early and is now 12 days old.
He was jaundice at birth so required light time-he's still yellow in the face and I'm constantly worrying he's more yellow or that we will have to go back into hospital for more tests.
He also was born by forceps so had 2 large soft lumps on each side of his head. I've been told these will take up to 6 weeks to go away but I'm constantly worrying they are getting bigger or hurting him.
My main concern is his feeding. He is breast fed and will usually go 3 hours sometimes 2 hours overnight. Health visitor said to leave him to demand it but I'm worried about going over 4 hours between feeds because he's so little, I don't want him to become lethergic.
Anyone have any advice!