sudden hard lumps 😕 tmi!

A
So I check my breasts pretty regularly although I have only just noticed a sudden change. Pretty positive they were both normal a couple weeks ago. 
I've checked them tonight and I seem to have hard lumps (well hard tissue) on both of my breasts. You can feel them a lot easier when I lift my arms up. 
They are directly above my nipples and aren't round. (I've tried my best to draw a diagram of where they are lol) they aren't identical on both of them as my left one seems to be rock solid down the side too. 
Anyone ever experienced this? I'm making an appointment to see my gp Monday but I will drive myself mad with dr google until then 😩