First of all Carmen it sounds like you are doing an awesome job and well done for persisting.

You may find that after drinking from a bottle Nicky is too lazy to work for the boob. It is harder for her. I'm sure you have more than likely tried this but I will suggest it just in case. Start expressing some milk out until you get your letdown happening and then see if you can get Nicky to attach and start feeding. This way she doesn't actually have to work too hard to get the flow started. YKWIM ??

Try this both with and without the shield and see how you go.

Seeing a lactation consultant is a great idea. Also maybe you can contact ABA. They might have some other suggestions for you. Also it's great for some support.

Huge hugs huni I hope you can get on top of your feeding issues soon