I Think I Have Kidney Stones Or Maybe A Kidney

i think I have kidney stones or maybe a kidney infection. how can i deterine whhhich one i have?? i have blood in my urine and my kidneys or bladder fills completely full and when I try to void, it's a very weak stream and it only voids about 2 - 3 ounces and sometimes there's there's quite a bit of blood and sometimes no blood at all but it's extremely painfull either way!!