milk supply going down

Megan

so my little one is 3 weeks old and in the NICU cause she was born at 28wks. ice been pumping and taking her milk to the hospital. at first I was getting 2-3 oz total. but now I'm not even getting an oz. I will be honest and say I did slack on pumping every 3 hours because there was so much that was going on between losing her twin sister at birth and the hour it takes to get back and forth from the hospital. but I've been getting more struck with the every 3hrs thing but feel like I'm not getting anything.

so my question is can anyone tell me some tricks to get my supply back up. I'm pumping for about 20-25 mins at a time.