Struggling

I've had an absolute nightmare establishing breastfeeding too, I relate to everything you've written!! We had a posterior tongue tie which was cut on Tuesday which I thought would fix everything but it's still really painful to breastfeed. I came home expecting to breastfeed but when it hurt again I was devastated.
We were recommended to see an osteopath who taught us so much. He said that although our baby's tongue tie had been cut, she needs time to learn how to feed differently as she'll be adjusting to her tongue's new position. Our baby was also a Ventouse delivery which I didn't know but apparently causes loads of tension in her jaw which can make breastfeeding very painful. We're seeing the osteopath over the next two weeks and hopefully we'll finally get somewhere.
I'm currently expressing and giving via bottles which has been really hard for me, I've cried every day and I'm so worried that she'll start to prefer the bottle to me.

Where are you based? My local council provided really helpful support for bf and also drop in sessions. Maybe you have similar where you are? For your supply you will have to pump 8 times a day to make sure you signal to your body to produce the right amount of milk. If you do that you can take time to get to the latch sorted pls don’t fret. It’s normal for it to take a while to figure it out for both you and your baby. The supply is the time sensitive thing and also making sure baby is fed. If you’re introducing a bottle then look up paced feeding and use extra slow flow teets, I recommend getting MAM 0 teets

I have enormous feelings of guilt too which I know are irrational but I can't help it. Have you looked up tips on how to improve your milk supply? Make sure you're eating and drinking really well and make sure to express between 1-5 overnight as this is when your hormones are the highest!
If you feel ready to give up then it's absolutely fine to do so, but if you don't feel ready keep persevering and seek further help, there's a very very strong chance you'll get there. Xxx

I’m sorry things haven’t been easy, it sounds like you’re doing a great job so far!
Breastfeeding is really hard, despite being ‘the most natural thing in the world’. Do you have a local breastfeeding group that you can get to? A quick Facebook search might help if you haven’t already looked into it
The lactation expert would have managed to latch baby with the tongue tie, as that’s now been sorted your baby will need to learn how to feed again - it could be worth getting back in touch with them to see if they can come out to see you?
With my first I decided to stop trying to BF about a week and a half into it, I really didn’t want to but the relief I felt when the decision was made and he was happy and healthy on formula meant it didn’t matter in the end anyway!
I hope things improve for you either way so that you and your little one can thrive together🥰

https://laleche.org.uk/positioning-attachment/

Try here for help, nipple shields are great if your nipples are unbearably sore but do nothing but worsen latch as they only allow baby to leave the nipple not part boob aswell. Midwives are unfortunately not trained in breastfeeding or checking tongue tie. Your HV is, so contact them asap and they have to come and help/show you. Just remember it's hard, so many mums have issues but seeking help can resolve them making it a magical experience

Try the national breastfeeding helpline 0300 100 0212 they available 24 hours a day, not sure where you're based but there's also the home start support groups its all free and they can come to your home to go through any concerns you have they may do things like this is in your area too? there's also usually breastfeeding support groups in places like the childrens centre you could look into, your baby won't need a lot a this stage as they still only have tiny stomachs so try not to worry about pruducing loads at this stage either just keep offering them the breast and it will get easier in time