Oh no! That sounds terribly painful and frustrating.
Where are you in Perth? Rebecca Glover is in Perth and she's a bit of a guru at sorting out tricky problems. Sometimes you need to see a few LCs to get it right.
It is entirely possible that there are several problems here. So there was no nipple damage or pain prior to 2 weeks ago? In the first month, was she gaining weight and growing fine? How many wet & dirty nappies is she getting?

So right now you're trying to express between feeds so that you can skip the occasional feed to rest your nipples, is that right? Does she take both sides at a feed? If not, you could express the other side while she feeds. Or, try expressing 30 minutes or so after the feed. You mightn't get much at first, but the more milk you remove from the breast, the more you'll make. It's quite normal for supply to settle down at this stage and for breasts to not 'fill up' - it's not a reliable indicator of supply. Likewise, babies are sometimes fussy and want to be at the breast a lot. output can be the easiest way to track input - wees and poos I mean.

I hope your LC apt is fruitful!