I was told rosé coloured urine was probably okay ,red wine colour needs investigation. Blood in urine does sometimes look worse than it is. A little bit concerning that your surgeon doesn't know what is causing it. I was told if the new joint was leaking you would probably feel quite ill. I note it is over 6 hours since you wrote this post. Were you given an emergency number to call or you could try ringing the ward that discharged you. Don't let anyone other than a urologist change the catheter.
You have obviously already discovered that taking it easy is helping, but you also need to keep mobile, for the reasons you said. Apparently not all hospital issue the injections.
I have been admitted to hospital after a dilatation of my joint with pure blood and clots hanging out of the penis. I was in for four days and they only flushed me out once. The "treatment" was just rest.
Thanks Chris