Why do I have a bloody discharge 4.5 months post-hysterectomy?

It's just a blood-stained discharge, brownish as though it's old blood. I've had nothing like this previously since my hyst. My hysterectomy was due to severe endometriosis (ultimately because of complete cervical stenosis so my uterus and right tube filled with blood) and they took my cervix but left my ovaries. There is no cervical tissue left now, which has been confirmed by MRI. I'm having my right ovary out in a few weeks because it's got progressively larger since the hyst, and also my middle incision (my hyst was LAVH) is herniated so that's being repaired. I've done nothing unusual in the last couple of days- I've cycled 25 miles but that's not made me bleed before; I'm not concerned about STDs because I've only had with my husband (48 hours ago- it hurt which it has since the hyst and is still achy now but that's not unusual) and I was obliged to use a gross toilet at a gig I went to last night but it wasn't that bad and the discharge doesn't smell or burn or anything, it's just bloody, so I'm not worried about infection. Pee's fine, tummy's achy but that's pretty usual. What's bleeding?? Is this normal and I just haven't noticed it before? My lower back is pretty sore but that might be because I cycled home with a backpack full of shopping earlier (9 kilos, 1.5 miles). My have been sore the last couple days but today they're fine. What's going on? Should I go and see my gynecologist again or quit worrying and wait til my routine appointment (Sept 21st)? Just any info would be great- this is really weird for me (and I haven't got any towels or anything either!!) Thanks very much x