Blood can be scary, but I try to remember what my mom(a nurse) told me about an experiment she saw in nursing school where you put a drop or two of blood into a bowl of water and it looks like there is a whole lot more blood than there really is. The purpose of the enemas are to reduce inflammation and if your blood is bright red, you know its near the bottom, so you might as well try an enema. My dr. told me to use enemas if I see blood as my UC is very left sided and is a lot like proctitis(very near the bottom of the colon) and it helps me. They aren't fun, but better than more drugs!
I hear you on not liking on call drs--when I pregnant and flaring while on prednisone, his advice was just up my prednisone a LOT and he didn't seem to get my hesitation at exposing my child to any more of that lovely drug.
Also, call your dr. just in case s/he has a better idea. Hope this helps!!