Pleeeaassese help!!

When my LO was born I was told to supplement with formula at the hospital because he wasn’t gaining enough weight so I did. Then my mother was super discouraging about breastfeeding while she was here for the first two weeks. and she made me feel guilty like he wasn’t getting enough so I kept up with the formula.

Now I want to exclusively breastfeed more than anything!! I’ve spent days keeping my LO at my breast and feeding him whenever he wants but he’s never satisfied. He’ll get so fussy that he’ll latch and then pull off of my breast and cry. Thank I’ll eventually offer him some formula and he’ll chug it like I haven’t fed him all day. I know this is only hurting my supply but if I don’t offer it, he will be miserable and can’t sleep.

So my question is how can I transition to exclusively breastfeeding? He’s 4 1/2 weeks old. I can tell my supply has increased slightly but it’s not enough to satisfy him. Please help! I know it’s not the end of world to offer some formula but I really love it and would love to continue for the first year.