Recalled for another mammogram after biospy

My Mum had found a breast lump and was referred to the breast clinic.  they did several mammograms on both breasts and an ultrasound on the breast with the lump.  They then discovered she had 2 lumps very close to each other, quite large and said they looked suspicious and worrying.  They did 6 biopsies and put a ribbon and clip in.  They said cases are discussed on a Friday then Mum would be contacted to come back in and that she could bring someone with her which is terrifying to hear

 

We gt a call unexpected today saying radiographer wants more mammograms as he wants a closer look and possibly another ultrasound tomorrow morning.   Since then we've felt sick and anxious as to why more tests as she was up there 3 hours last week and had 6 mammograms and an ultrasound before the biopsies.  What could they have seen or be looking for as they told Mum nothing and shes not slept the last 9 days with worry.  Anyone else had this before?