I would say definitely follow fallcolours advice, I have recently had a hell of a time for nearly a yr with an abscess that I left too long, tried to ignore, and it got bigger, deeper, and worse. My initial seton surgery worked but the abscess continued to tunnel, so I had to have a second surgery and mushroom drain inserted, which I still have.
Mine drained blood too – pus-filled blood, which smelt infected. It is very gross, but hopefully you get it seen to soon. I left mine too long and I wish I hadn’t, but I do also blame my negligent Gastro (who I have since fired). Mine would drain considerably, but it still wasn’t enough, the abscess was huge in the end! its taken over 6 months and its still not healed.
I hope you get the help you so need and soon. Hopefully you can find a colorectal surgeon who specialises in IBD. They really understand what you’re going through (and the PAIN)!