“What could be the cause of this and why does blood in urine come and go?”

In July, I went to my gp because I noticed that my urination would come out then not or it would come out as trouble. Then I started noticing the kidney pain coming too with burning pain when I pee and I would pee only twice a day. I went doctors and I was told I had a kidney infection and blood in my urine. It went away after two weeks. There have been times where the pain has been really painful and times where my urine would stop completely then come after after days. Recently, I’ve only been peeing once a day and the pain in my kidney is in both and spreads to much upper stomach, bottom stomach, groin and thighs and insomnia from the urge to urinate and pain. I sometimes have to force the urine out if I feel like I won’t be able to focus in my class at college. I had another urine test and it came up as clear so no blood but a trace of protein. Yesterday at night I noticed blood in my urine. I’ve got a ultrasound next Wednesday for my bladder and kidneys.