Had a lump checked last year but it’s grown

June of last year I had a lump in my breast checked out, my breasts are quite lumpy anyway but this lump was very obvious and marble sized. They did mammogram and everything but said it was nothing to worry about. But as of late it's increased in size and I'm scared ***. I know fibroadenomas etc can all grow and be fine but I dunno. I'm 37.