@happymummy12345 Came back for this - absolutely, the feeling of failure can take a long time to overcome when your baby is poorly and especially when your role is changed by the environment of NICU. I’m so sorry you had to go through it too 
In fact it has been noted many parents suffer with a form of PTSD afterwards.
It took two months for my twins to be strong enough to even attempt bottle feeding, by then my paltry supply of breast milk had dried up. I was pumping blood.
I got some very snide comments from some of the NICU nurses (thankfully they were minority) about why I must persist and I too already felt like a failure. My twins were born very premature at 720 grams (DD) and 980 grams (DS). Without the care given by multiple valuable nurses and doctors they wouldn’t be here.
Without specialist formula to gain weight I wouldn’t have been able to bring them home when I did.
Like you, I know I bonded with them the moment I saw them, the first time and multiple times since that I held them, first when they were in their incubators so one hand on their tiny head and one resting on their bum. Then when I was able to actually cuddle them. Sing to them, talk to them, read to them and so on.
When broad strokes are applied to the debate between formula and breastfeeding, such as this supposed magical bond only offered by the latter, I feel that information regarding oxcytocin and how this is generated and it’s relationship to, well, relationships as well as mental well-being and memory recall, is vital. It saved me at that time from my obsessive fear that my ‘failure’ to have my babies thrive in womb and be delivered on time at a better weight - would mean our bond would be forever altered.
I know that every decision I have made around the care of my twins has thus far brought them further, quicker than any of the Paediatrician’s predicted. As with you, I know I have my precious bond with them as well. How they were fed has little impact to the many other ways we interact with our babies, toddlers, children etc. in forming that bond. 