Found hard lump that doesn’t move in lower part of breast

Hello,

I am 33 and I had my second child 6 weeks ago. 3 weeks ago I found a hard lump under my right breast whilst breastfeeding. I thought this was a blocked milk duct and got given antibiotics but it didn't go - only the red and soreness over it did. They referred me to the breast clinic where I thought I was just going to have an ultrasound but they ended up doing a biopsy as well. They said it definitely isn't a blocked milk duct and I have to wait for 2 weeks for the results. Since coming home I have been on google (I know this is bad) and I really feel like this lump could be cancer. It feels hard and feels deep and connected to the tissue underneath. It is also quite big - about 2-3 cm in length but it is quite thin. What else could this be apart from cancer if it is connected to the tissue underneath? I am terrified. Any advice would be appreciated thank you xxx