Pretty much the same here. I'm about
6 weeks out from davinci RALP. had some blood at the end of urinating, particularly after a bowel movement, and passed a few spongy clots. that has now subsided. the burning sensation at the end of urinating at first was due to blood, I guess it has a different pH, or something. Now I still get some of those feelings at the end, but much less, and reducing with time. The urethra stretch feeling is less than you describe for me, but still there is the sense that you wish there were just a little more rope...
Sounds pretty normal and seems to lessen with time. You should, of course, bring it up with your MD at next visit. Best of luck.