My twins were born by Ecs five weeks early and were resusicated and taken to nicu before they'd finished stitching me up - didn't lay eyes on them for 7 hours, held one the next day but didn't hold the other for quite a while. I immediately started expressing as instructed, within hours of my section. Almost drop of colostrum went to the smaller, sicker twin as he was too sick for formula. tgere was no skin to skin and very little physical contact in the first two weeks, for one particularly. When I was able to try latching them, they couldn't latch well and it was incredibly painful, all the milk was spilling out of their mouth and down me but the hospital kept telling me it was fine. One came home after 2 weeks with his ng tube - I would feed him for up to an hour then he'd still be starving so I'd have to top up with formula since his brother needed all the milk I was making. The other was in for 8 weeks and eventually they were able to get him stable on medications and ebm plus formula for medical reasons and other things. Within two days of him coming home, he got sick and eventually ended up in hospital with whooping cough - I had to stay in a recliner next to his bed for 11 nights and barely got to pump. After that my supply dropped from 1 litre a day to 300 ml.
At the time I was part of a breastfeeding group on Facebook and the attitude towards FF and even pumping was just hideous. Those women made me feel like utter shit. I became obsessed with pumping, was doing it every 2 hours and still not getting 25% of their daily needs so having to supplement anyway. I spent most days in tears, my babies left in their swings or baskets while I pumped. I barely held them in that time. I had terrible depression but didn't realise it at the time.
I ended up leaving that group after a thread denying that formula shaming exists despite seeing it constantly in the group. I was constantly told I could have breastfed if I'd tried harder, that I was lying when I said one needed formula for medical reasons (absolutely true), someone said they didn't agree with formula for "any reason", that the reason I was depressed was because my body believed I was killing my babies by starving them so of course I was depressed. It was the most toxic environment I've ever been in.
I finally saw some sense about 7 months and stopped pumping. Looking back now I must have been insane to continue like that. Failing to BF was definitely a big factor in my depression but I believe the hormones also played a part since when I stopped pumping and my periods returned it improved significantly.
I'm still heartbroken I couldn't bf - it never occurred to me that I wouldn't. Believe me I tried everything and persevered with pumping. in such difficult circumstances far longer than many others would have but I still feel a failure thanks to the attitudes I encountered. I worry that they will have health issues because they weren't bf but fortunately so far that doesn't seem to be the case / I worry more that I was so focussed on pumping that I didn't give them enough focus when they needed it.
Sadly anecdotal evidence means nothing (when little twin had whooping cough he was in hospital with a much bigger baby of the same age who's bf and been in and out of hospital ever since while we have never had to go back, but that's not evidence of anything and I don't get why people turn to stories like this). I do think breast milk is undoubtedly better for baby - it's not processed, it's what baby is supposed to eat and it seems foolish to try and argue that's not the case to me. However, I doubt the extent of some of the claims and the veracity of some of the studies to be honest.