FTM 2 week old low supply

I’m a FTM with a 2 week old and I pump my overnight feeds (1 am, 4 am, 7 am) and my husband bottle feeds them to our baby. I am struggling with low supply as I have only been getting 1 to 2 oz total per pump!! How do I increase this? We have had some struggles, including having to supplement with formula since he was born due to being born @ 37 weeks and having weight gain and glucose issues. I also have mastitis that is just finally clearing up. I’ve been stressed with a low appetite too. I know I should eat more so I’m trying. But what else can I do?