I found nipple shield useful to get the latch going again as it is the same texture as a bottle teet. Lots of skin to skin. Food made from oats are good at boosting supply.
My biggest tip is get to a local peer support group, la lache league or the breastfeeding network or your local council. There should be something you can attend for peer support and advice
Often thrush on the breast is present at the same time that the baby has thrush on the tongue and it can be passed forwards and backwards between mum and baby if not treated. Usually the baby gets Nystatin drops to clear it up and mum gets a cream… at least that was the case a couple years ago for me. Neuner’s Nursing Tea is good but there are loads of other tea alternatives if you don’t like the flavour of that one. It is a bit of an acquired taste 😅x
Chamomile tea!