Waiting for breast biopsy results

Hi, I went for routine mammogram screening 19th June (no symptoms). A week later I got a letter with an appointment at hospital for further tests within the next few days. At that appointment, I was told something had shown up that wasn't there at my last screening, 3 years ago.  Whatever it is was showing also on the 3D mammogram.  The nurse said I needed an ultrasound which should give more info, but that didn't show anything.  Also the nurse could feel no lumps or see anything odd.  I was told that I needed a biopsy as its possible that I may have cancer.  Had the biopsy the same day and see a consultant for the results 17th July.  I dont know why they told me it may be cancer - why didn't they wait until they know the results?  And why do I need a consultant appointment - surely that wouldn't be needed if everything's ok?  Just a bit confused and obviously worried.  Thank you x