"Everything was done too quickly"

I was referred by my gp after I discovered a breast lump. They only did an ultrasound and decided that it is normal breast tissue. I still have not understood how it is possible that I clearly touch a breast lump and the doctors can't find it. And, in any case, the doctor didn't show any interest to explain to me the situation although I made it very clear that I don't understand. I left the hospital rather puzzled and certainly not confident that my problem was given the attention it deserved. I feel like all they wanted was to get rid of me as soon as possible. However, I should note that the nurses and the radiologist were very polite. The doctor was not rude, it's just that I spent many sleepless nights over this lump in the past weeks so I was hoping I would get some explanation of what it is. You are a doctor and you see a person worrying they might have breast cancer. Don't you feel like you have to talk to them a bit more than half a minute?