It's horrible that after everything we have been through - there never seems to be an end to the worry and fear.
I can't really add much other than to say that I've similar experience with bleeding after using dilators/having sex (I finished treatment before Christmas so only been using them for a few weeks). I was also told some bleeding afterwards was normal while the scar tissue was being broken down - I have no idea how much blood would be "normal" though. I mentioned it to my consultant at my last appointment and she seems to think it was fine. I think its something I'll keep an eye on (make sure it doesn't get heavier) and will be mentioning it at every check up.
It's so hard not to worry and think the worst after everything we have been through. Be sure to mention it at your appointment next week and sending you loads of positive thoughts.