As the Mum of a tongue-tied baby (not diagnosed until 6-8 weeks old) I think this sounds very similar to our situation. He used to arch his back and really fight against the breast, but when given a bottle was a lot better (you mention you've given a bottle, but not whether the same problem occurs?). We spent a lot of time perfecting the latch too, which at the end of it all was a futile exercise when he was still tongue tied as it didn't make any difference to his ability to be able to feed. We eventually got it fixed at Kings, and things steadily improved. His tongue tie, while "mild" in terms of being able to see it (it wasn't obvious at all to look at him) was bad enough to affect feeding. This may not be the problem in your case, but I just wanted to give my experience. Well done for perservering, I know how stressful it is in the early weeks with a baby not feeding properly. Good luck, and keep us updated. Pippa x