Found a lump

I felt a lump in my right breast. It’s fairly tender and it does move around slightly. I met with my physician yesterday and she agreed that due to the asymmetry between both of my breasts and that it feels tender, I should have a mammogram and ultrasound. I have to wait a week before my appointment and I am so worried and stressed. I have no history of breast cancer in my family. I’m only 35. I’m scared.