Nervous about a new lump

Im 30 years old I was diagnosed when I was 27 with stage 2b breast cancer in my left breast. Extremely young I know lucky me. I did chemo, bilateral mastectomy, radiation, on the great and wonderful tamoxifen for almost 2 years now. Literally about to switch to the other meds since I've have a complete hysterectomy. Had a scare in September which ended up being cellulitis that one was fun. But few weeks ago I noticed a lump around my right armpit edge of my breast called docs office the moved my appointment up a week which makes it Wednesday this week. But I'm pretty much secretly panicking right now. I know that it's rare for it to change sides but so was my age when diagnosed. Then google is not my friend but I can't stop myself from researching. Then those results terrify me. I'm mostly private and I don't want to worry friends or family if its nothing also they don't really understand any of it really. Then that leaves me sitting with this fear alone and trying to tell myself one more day (pretty much) but still on the verge of a mini majorish freak out.