Dear friend, welcome to HCM.
your symptoms can have many many differentials and only detailed clinical and lab investigations can tell what it is.
if you do not have burning urination, colocky pain from flanks to groins, blood/ pus in the urine, vomitting also, it is unlikely a kidney
since it is 3 weeks, you should get through examn. and routine blood labs, an ultrasound
of abdomen and pelvis.
nodes usually enlarge in head neck infections, and left neck glands sometimess in stomach problems.
so, follow medical advice
take care and pl. keep me posted on your progress.