Followup tests for kidney infection were negative after i finished my medications, but three days later i have particles (not cloudy tho) in my urine?

Sediment: Infection means bacteria growing where it should not be. Your test for infection in your urine was negative and that is good. Sediment in the urine can be from infection, HOWEVER, there are other causes of sediment in urine that are benign. Try increasing your oral hydration, add lemon tea as well as water and juices to goal >60 oz for a few days and see if the sediment improves. Be well.