He's so little - he'll be back to the breast if you stick with it. Great to hear you're getting help from an LC.
Have you also tried calling the ABA for advice?
Keep him close to you, if he doesn't want to feed, no worries, try not to associate stress with feeding. You could also try having a nice warm bath together (might be a bit tricky with such a little baby, but the change of scene and relaxation factor can help)
All the best