Yea I had it for nearly a month, it's nasty and hard to get rid of and unfortunately sees the end of a lot of breastfeeding but stick at it if possible, you'll be so glad you did when it's gone!
I found he worst pain to be he hour AFTER a feed, the stabbing and burning was so intense! My nipples we're in bits as well and I couldn't even shower without a bikini top on because I couldn't handle the water on them.
You need to go to the gp and get cream for you and bystander for baby, you'll both need treating. However, this treatment wasn't enough for me, so I went back and was given same again but also a tablet to help shift it and by keeping up with cream and babies treatment we finally got rid.
A few other things we were doing to help the healing were: lots of topless time, lots if washing (no soap in boobs), alternate thrush cream and Lansinoh, and throw breast pads away as soon as they wee damp, thrush likes wet and warm places,
It's stubborn and you really have to commit to getting rid of it but you'll be so pleased when you're on the other side. You have my sympathy though, it really is agony xx