I had that problem while using it, and by coincidence while I was last using it I had a blood test.
The blood test come back with extraordinarily high levels of creatinine in my system.
Turns out that the vast majority of the creatine we take turns to creatinine.
https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/creatinine
Creatinine is a toxic substance which is filtered by the kidneys and excreted through urine. Hence constantly needing to go.
Apparently taking creatine capsules can help the body to absorb more creatine and produce less creatinine, but when we use the basic monohydrate powder, a significant percentage of the creatine already turns into creatinine in the water before we have even started drinking it.
Or so I have read anyway.
I am no scientist so I can only speak from personal experience, but I can tell you categorically that I was only using 5 grams of creatine once per day, and I didn't even do a loading phase, and my creatinine levels on a blood test were through the roof, so I stopped taking it, and the levels went down pretty much immediately.
My next blood test was 3 weeks later and my results were fine.
I haven't taken it since.