Question for skinny moms!!

First off please don't get all butt hurt because of the title🙄

I'm trying to find someone who may be in the same boat as me.

I only gained 20lbs during pregnancy and prepregnacy I was 135 5"4, fit, I used to lift. Anyways I'm 15lbs below my pre pregnancy weight and I'm trying really hard to gain weight. I've noticed my milk isn't as fatty and I want to know if anyone else is having the same issue.

I did have a oversupply. I was pumping and nursing but now I barely get anything is anyone else in the same boat.... worried my baby isn't gaining weight as rapidly ☹️