Why am I still bleeding?

Lithotripsy for a couple kidney stones 4 weeks ago, stent removal 3 weeks ago, which was absolute hell, but the pain has mostly subsided, but I’m still peeing blood. I’ve been peeing out blood clots since the stent removal, and the past few days my pee has turned bright red again! Urine sample last week was negative for bacteria growth but otherwise would suggest infection; however, I’ve been on an antibiotic for a week now, and I’m still having issues. Ultrasound of kidney+bladder on Friday didn’t pick up anything particularly concerning either, besides the “non-obstructive” kidney stone that the urologist neglected to address during lithotripsy even though they said they would. What the hell could be going on at this point???