B12 Sleep Walker

It's bizarre– the past few days I've been waking up to random bruises all over my body. I usually remember when I bump into something or I at least have the notion that there is some potential for future bruising, but the occurrence of these ones is an absolute mystery to me. What makes them strange is mostly their location: one on the inside of my left wrist, about a quarter of the way up my arm, over my radius, slightly larger than a quarter and dark purple! How does one bruise there, might I ask? It's such an odd location, and yet the spot is extremely sore. Then there's another on the left side of my lower back, and it's causing me pain when I lean against my pillows. How the....? And one more on my left upper thigh, but situated so that I can't imagine having sustained it from walking into a table or sharp corner of some sort. It's just kind of creeping me out, because I look like I've been assaulted, and I'm quite certain that I haven't been. When I told this to my co-worker, she suggested that I might be sleepwalking, and bumping into things. Now that is a good explanation. But why would I be sleepwalking, and why all of a sudden? I've never engaged in any acts of nightly wandering before... I'm psychologically pretty sound, the stress levels are low, I've been sleeping enough to dream at night, no change in diet, exercise blah blah... but I'm waking up bruised, as if I'd slept on a bed of rocks. The only other solution I could think of is that I'm anemic and just bruising easily... that's probably it.