I honestly expected breastfeeding to be easy - it was anything but.
Ds1 developed neonatal jaundice, and was given phototherapy - initially I was told I had to feed him 4-hourly, and that went OK. Unfortunately his jaundice worsened, his phototherapy was doubled (a second set of lights), and I was told that he had to be fed3-hourly and I was told I had to top him up with formula! as he needed extra fluids and calories - I trusted the medical staff on this, and started supplementing him with formula, and this very quickly caused problems with the breastfeeding.
By the time we got home, when ds1 was 8 days old, breastfeeding had stopped almost completely. I decided to try to resurrect it by hiring a hospital breast pump from the NCT - I pumped after every feed for 10 days - on day 1 I produced 4.5oz, and on the 10th day I produced 4.5oz - at which point I decided I had clearly failed at breastfeeding, and went onto solely formula feeding.
With ds2, I was even more keen to succeed at bf-ing (I was convinced my earlier failure had contributed to me getting PND) - but I had problems this time too. He fed constantly, but with a fairly weak suckle, and having lost 10oz off his birthweight, he hadn't regained that at 6 weeks old. My HV was coming daily or every other day, telling me she wanted ds2 to have gained at least half an ounce a day by her next visit - which he didn't. On one visit, she brought up formula feeding as a possibility, and it told her I was really keen to succeed at bf-ing this time - upon which she told me, "Well, I have to think of the best interests of the baby!" I asked her how she dared suggest I did not have my baby's best interests at heart, and told her to leave my house at once.
A few days later, ds2 woke up from his afternoon nap with breathing difficulties, so, after my GP had visited, we were sent to the paediatric ward. We were kept in, and he was given antibiotics for a chest infection - but the staff were far more interested in his lack of weight gain, and basically we were kept in until he started gaining weight. I heard nursing staff referring to ds2 as 'Failing To Thrive' - and in the end, I agreed to start supplementing with formula. Ds2 did start to gain weight, but supplementing with formula killed bf-ing for me again. I had failed again. I got PND again.
With ds3, I mixed-fed almost from the word 'go' - I bf-ed during the day, and gave ds3 a formula feed for his last feed of the day and for one of the night time feeds. As long as he had two formula feeds within each 24 hours, ds3 gained weight at an acceptable rate. If I cut it down by even one feed, he stopped gaining weight.
I have struggled for years with my feelings of failure from this - it seems to me that every other woman can feed their babies except me - I am very good at self-criticism, and being harsh towards myself - and this has contributed to my long history of depression.