I see it's been a while since you posted. I hope things have improved I'm a FTM and not a specialist, but I experienced some of the same frustrations. My LO is 2 months. We had lots of difficulties in the begining especially with very very sore cracked bleeding nipples. I had the same nipple pain showering and if my LO ever hit my nipple while trying to get him to latch in the begining, it made my stomach turn. It hurt so much.
I have the itching burning sensation when I nurse. I feared thrush. An LC looked into it and said that was not uncommon and not thrush. Not really anything to do about it, but you'll notice it less and less.
I nursed and supplemented with formula in the 1st 2 weeks. For various reasons, I was only puming and bottle feeding for 2-3 weeks after that. We were able to start nursing again and my LO is exclusively on breastmilk now. I drink Organic Mother's Milk tea 3x a day. I bought it on Amazon. I get 1-2oz more during a pumping session than I was getting before. I think it took a week or so for it to really kick in though. Hope things get better. Like everone else said, do what you can and what ever gives you peace of mind. Whether it is breastmilk or formula or a combination. Good luck.