Mix feeding help??

I EBF my 6 month old but as of late she is so upset at night after her feeds. I've been giving her expressed milk from the day afterwards and she drinks it all (about 170ml) on top of feeding from both sides for a good 30 minutes!

I think she is frustrated with the flow and supply

I'm finding it difficult to pump extra every day, whether it's because we are busy, or when I do I don't get enough for one full feed.

I'm thinking of introducing a formula feed to replace that one

Has anyone got experience with this? How do I go about it?

Any help would be great 😊

Avoiding drs surgery's at the moment with the illnesses going around! Might call a help line

But thought a good place to start was here 😊