Lump in breast

I’ve been having a lot of pain and soreness in my left breast, my breast don’t normally get sore not even before a period so it’s been out of the norm and was concerning but just put it down to possible muscle strain from sleeping crazy with my kids all over me. I’ve also had discharge once but I finished breast feeding my daughter about six months ago and ffigured it was old milk because it was milky clear color. But a few days ago I found a lump in the top center of the same breast and anxiety is now through the roof. I went to the doctors the other day and had it checked by the Nurse practitioner who felt it right away. She said there was a nodule but felt small so that’s good (don’t really understand why) She also said caffeine, as I drink coffee every morning can cause cysts. She didn’t say whether it was concerning or not but I’m freaking out because she’s sending me for an ultrasound and mammogram if indicated. I feel like if she wasn’t concerned this wouldn’t be an option. 😰 my boob is no longer sore. i myself can’t tell if it moves or not and I feel when I try to find it I can’t pin point it like I did a few days ago. It doesn’t really hurt in that area either. I have an ultrasound and mammogram (if indicated) scheduled for Monday but I am scared shitless. I feel like I didn’t get any reassurance from my doctor and that makes me more worried. Words of positivity?

Also I’m 28 year old