Is it too late?

I got a really bad start with breastfeeding for many reasons. Baby being premature being the biggest because he was on oxygen the first week and then still not mature enough to latch and nurse for almost two weeks after that. I had delayed lactation...lactation consultant thinks because I was having to rely on the pump and she doesn’t think my body was responding well to the pump. So because of that my supply took a major hit and baby had to be supplemented in the NICU with donor breast milk. Then we both got thrush and the neonatologist wouldn’t let me nurse until we were both clear of it, so I had to rely on the pump again which didn’t help my already low supply.

We just hit 4 weeks postpartum and just got discharged from the hospital and he’s a good little nurser, but I’m still having to supplement because my supply is still low. My mother in law suggested trying to just nurse him without supplementing for a day or two and feed on demand, even if it’s every hour, to signal my body to make more but I’m so nervous to do that because his weight gain has been a big concern with him being a preemie. I’d be terrified of him losing weight. I never got that surge of milk when my milk came in that most women describe..it happened EXTREMELY slow. Is there any chance of bringing my supply up to meet his needs this late in the game? Any suggestions how I might do it?