exclusive pumping mamas

I’m 8 days PP & my milk still hasn’t fully come in 😣 I’ve been exclusively pumping since my LO was a couple days old due to latching issues, I’ve also had to start supplementing with formula due to weight loss. I really want to continue this breastmilk/pumping journey but I hate it 😭 it makes me SO anxious. I’ve been pumping every 2hrs for a few days but I feel like I’m getting nowhere. I can barely ever get more than an ounce out of my left breast, my right one does okay but as my baby grows I don’t feel like I’m gonna be able to keep up. my nipples hurt, my back hurts, I already feel like I’m failing my baby because I’ve had to start supplementing. I never thought it would be this hard & I didn’t mentally prepare for any of it because I thought breastfeeding would work out, so I’m seriously at a loss. I just want to cry. if there’s any mama’s that can give me some advice, words of encouragement, tips on how to up my supply - anything! it would be so appreciated.