Obsessed! Help!

hi I'm 21 with no family history of BC and found a lump in my right breast, had it checked and the dr found another in the same breast but said it's just fibroadenoma.

A few months earlier I done some fund raising for breast cancer uk and a women had done a speech about how she was 21 and felt a lump and the drs misdiagnosed her! So I kept worrying about these lump and consistently checked my armpit too! Until I felt what I thought was a lump just in my armpit - I ended up in a&e out of sheer panic... That dr couldn't feel anything in my armpit and said the lumps again were fibroadenoma and the problem was infact in my mind. This cleared my mind and only up until about 2 weeks ago I felt I was getting better.

And then I checked my left breast - to which I felt a thickening and lumpiness - I'm now consistently checking and panicking comparing the size to my other (seeing a size difference but not sure if it's in my mind)

Please help!! I don't know what to do it why I'm so obsessed ! That one speech has had such an impact on my life and I shouldn't let it but I can't help it!!