Feeling very guilty

BG
So I have been trying to breastfeed (pump and bottle feed because my girl won't latch) for 3 months and my supply has been steadily dropping even though I have tried EVERYTHING (supplements, herbs, changing diet, even medication) to try to increase it but it's not working. I have had to supplement with formula for the last month. It has been stressing me out so badly. I feel like it's just not working out with for me, but I want to give my baby as much as I can. I finally broke down and told my hubby about it and he said to give it 1 more week and if I still feel this way then maybe it's time to stop. I feel so guilty because I want to give my baby the best, I want so badly to breastfeed. It kills me that I can't do it and I feel like I'm letting everyone, especially my daughter down. Has anyone else gone through this? What did you do? 
I just need some support. I'm feeling so horrible.