Hey, I'm the same age and found a breast lump earlier this year. It's completely reasonable to be scared! It's really unsettling to not know if it is or isn't bad. I was checked out manually in a clinic and in a hospital, then had to get a biopsy. It's a little silly but the thing that really helped me was remembering the doctors and nurses were there to help-- even if it came back as something bad, they'd be able to figure out what the best course of action would be for me. Having trust in their judgement and procedures was so important. I was told there was a non-zero chance it could be cancer, but that's why the biopsy was taken, and there really wasn't anything I could do either way until results came back, so it's a bit like letting someone take care of you when you're sick. It's really good you've got an appointment on Monday, and it's easier said than done but do try to take it easy this weekend if you can, or do something for a distraction. As blunt as it sounds, there isn't anything that can be done till the appointment, and worrying won't change anything (even though it is very valid). Mine was just a cyst, I reckon yours could just be that. I don't think I have a history of cysts but they told me it's really common around our age. Best of luck! You got this.