Milk Supply

My LO is 4 weeks old. We have been BF or at least trying too. I nurse as much as possible but I also supplement 1-3 bottles a day. Usually in the evenings when I have my 4 other little ones at home. All day and all night I try to nurse her but she’s always fussy, doesn’t sleep and at 2 weeks she had 0 weight gain. I started pumping and all I get is MAYBE 0.5 a session which I do every 2hrs. At night I nurse her almost every hr. She nurses and sleeps from 11pm-5am.

What else can I do to get my supply up. I want to at least be able to feed her enough for her to sleep well.

TIA