HI, We Have A 3 Year Old English Bulldog. Had

HI, we have a 3 year old English bulldog. Had uti treated with antibiotics. Swollen lymph nodes in neck, thought from uti? After a week on antibiotics, urine shows no infection but blood in urine. Blood work all normal. Lymph nodes still swollen. Now they want to do ultrasound of kidneys? Then biopsy lymph Nodes ?? Thoughts? Answers. Cancer? Help, as it's hard to trust vets.....