I'm really sorry to say this and I don't want to scare you or put you off, but when I was in your position whenever I posted on Mumsnet about it, everyone would tell me it got better eventually although the length of time would vary ('the first two weeks were the worst' 'after 6 weeks it was much better for me' etc etc). I was like you, I had severe pain, I had the breastfeeding support workers out to me loads of times, midwives, nobody could see anything wrong with the latch although it clearly was wrong as DD would latch at an angle all the time and my nipples were coming out lipstick shaped with blisters across the ridge. We had a tongue tie referral just to double check, but no tongue tie. I tried nipple shields which did help a bit but it was still sore, and eventually sometimes she would suck my nipple through the holes of the shield, causing blistering from that too, and I already wore the largest size.
I EBF for 6 weeks, and combi fed weaning her gradually onto formula until 12 weeks. I was absolutely devestated that I couldn't hold on for longer but it never got any better in any of that time. My nipples are permanently deformed I think - she's nearly 4 months now and they've healed as they're not sore anymore, but there is what seems to be scarring I guess and my biggest blister the skin has sort of stayed in a blister shape. Also my mental health was appalling throughout that time, I have previous history of depression, and I was crying all the time, feeling suicidal etc. I really wish I had just moved to formula after the first fortnight or so when it was clear nothing was improving after specialist breastfeeding support, and saved myself all that agony, both mental and physical.
You are doing an amazing job and I commend you, and I am a big advocate of breastfeeding, but I thought I should share my story with you, because nobody told me it might still be agony at 12 weeks, and it was, and if I had known that might be the case, I would have cut my losses much earlier, so I feel I owe it to you to share my experience too.