Yes, you are in the wrong section of mumsnet here - this is not our area of expertise!
You could try calling the Breastfeeding Network Supporterline (0300 100 0212) where there are lots of knowledgeable and well trained mums who can give you good information.
Good luck with this, must be so frustrating for you and your baby. How old is your baby?
It's great that your baby has had the tongue tie snipped, but now she kind of needs to learn to feed all over again, using a different sucking technique. She will probably be much more efficient than she was before, once she gets the hang of it. Nipple shields might be useful for you on the short term, but should be ditched as soon as possible really.
Please do call the supporter line. In the mean time, it might be helpful to do "skin to skin" (strip off and spend the whole evening snuggled up with your baby - don't forget to take a good book / box of chocolates/ the television remote control with you). Babies often feed better when they have that closeness, and can feel your skin. Also, has anyone (midwife, breastfeeding supporter etc) talked to you about how to get the best positioning and attachment? Can't link on my phone, but if you type "positioning attachment nhs" into Google, you will get some information.
Hope you have a good night tonight, with lots of lovely night feeds 