Hi Meadsie,
My DD was slow to gain weight and deemed a "failure to thrive" baby, great to instill confidence in a brand new mum . I struggled early on with breast feeding due to lack of support. I was exhausted and upset as I ended up being railroaded into comp feeding and I was pumping at any spare moment to try and up my supply. It was really stressful. i just wanted to offer some and say that i am sorry you are going through this tough time. I hope the cloud starts to lift soon.
I tried to stay positive by not taking a lot of what some health professionals said to me to heart ( a nurse told me my baby was not crying for milk because she was too weak to cry, she was certainly not too weak to cry!!)
I also ended up not obsessively weighing her all the time as it was adding to the stress, just went off the number of wet nappies etc
Have faith in your body and your ability as a mother. You are doing a great job and your LO is doing all the right things, you know them better than anyone x