Advice - I'm 19 years old and a big dense lump has been found in my breast. I don't know how to feel. So many emotions

I don’t know if people even use this form anymore, so hello! I hope someone reads this and can respond. Because I don’t know what to do, I’m 19 years old and have been to the GP. I had leaking breasts with blood and have had lumpy breasts for a few years. My first GP when I was around 17 dismissed it as me having “More growing” to do: but after getting a an exam this year because it was SO ITCHY. And every time someone gave me a hug I wanted to die from the pain, turns out I’ve got a big dense lump that’s not really a lump and I’ve been referred. Like what do you do. What do you think? Feel? And how do you stop loosing your mind?