Thanks guys. I really appreciate all your advice.

I gave her a few days and tried to feed her in peace when I could and aside from a shocker of a night last night, she's been a bit better.

I tried using the pressure on boob like mentioned and it's helped so far.

I think it could have been stress/worry messing with my letdown.

I guess my only concern now is her weight.
I know I shouldn't compare her too much to her sister, but they were same weights at birth and followed the same path up til this point. To think, they used to tell me Munchkin wasn't putting on enough and she was 5.3kg at this point! (I stopped seeing them after a while.)
The only difference is that Munchkin was formula fed.

But yeah - I'm a worry wart.