"Now sitting here with boobs like rocks. I wish the moment you decided to give up bf your milk dried up instantly! Seems such a waste. The whole drying up gradually seems to have sparked a big guilt trip"
Sorry I can't do proper quotes. A huge number of women give up at four months and it wouldn't occur to them to feel guilty about it because they have breastfed their babies. So have you, and then some. I'm not trying to urge you to give up, but I do think you should have some perspective on the guilt.
That said, here's what's happened to me. I went down to four pumps a day for a week, then three, then two and am now on 1. My milk supply just VANISHED from producing (only) 400mls or a little more when I was pumping 6 or 7 times a day, to less than 100 today. I had one day of very hard painful breasts when I went down to 1. THIS made ME sad and guilty, so you can't win. I love giving my daughter bottles of breast milk, and now I'm just giving her a tiny dribble of it, supplemented with more than the same amount of formula, and formula, godloveit, just doesn't give you the same feeling of I-am-nourishing-my-darling. The truth is, I wouldn't have given up so quickly if I'd stayed in the same place, I'd still be doing my 6-7 pumps a day, and I'd still be spending up to 4 hours a day just wired to the machine.
However, now I've stopped, apart from the twinges of guilt because there's no more milk, I also feel so much relief, and am much more relaxed because I can spend time with my baby and don't have to fit the time we go out with working in my next pump. It was awful having to tear myself away when she was in a cute laughy mood because I had to go and pump and if I leaned over her would start spraying her with milk.
"related to my early failures"
NO! Go and tell your husband you said that and get him to hold you and kiss some sense into you. You haven't failed. And your baby didn't fail. You just didn't get it together from the get go. These things happen sometimes - I wish I'd known this beforehand, although maybe it wouldn't have helped. I was lying in the bath with my baby today, and I was lying back with her on her back, laughing up at me, kicking my face with her little warm feet, and I was just so perfectly happy, and we just have to look forward to all the moments like that and stop obsessing over the weeks when we couldn't make anything work. They don't count. They don't get stored up to mean anything later. It's just good from now on.