20 year old and worried

Hi.

Recently my breast have been weird. They look big and then small. Im not someone that checks her breast regularly to see if theres anything weird. But these past weeks ive been checking and getting really freaked out. I read some of the stories on this site but none look like mine.

One of my breast is smaller than the other one, but this isnt the main issue. On my small breast it feels okay. Nothing weird. But on my bigger breast I feel a weird lump. I am aware that usually you feel little grains on the breast, but i happen to find a very big lump on mine. Maybe the size of a grape? I dont know if its because Im young and now im starting to get different breast tissue inside but it's been really bugging me.

I have family that have died of breast cancer. At very young ages too ( not too young like my age but on their early 30's) and I get really concerened. Because my smaller breast FEELS completely normal and my bigger one (which is not that big it's a size feels this weird bump on the top side. It feels sore sometimes too. But I am still scared of checking them and something appearing (or not appearing and me actually having BC) Also when Im on my period, my breast never hurt. But lately if feels heavy and it inflates like it becomes bigger for a few days and then smaller (I dont know if Im hallucinating because Im paranoid) but still. I'm just very concerned. And on my nipple area there happens to be a little bump too. Like if it were a second nipple. (BUT HOW COULD THIS BE??) and I'm getting FREAKED OUT.

Thank you for reading my concerns.