I have low iron too, the result of heavy periods. I didn't have any fatigue issues from it, but I was starting to experience restless legs at night, which can be an anemia symptom.
I didn't even realize my periods were heavy until a friend talked about being diagnosed with them, and when she talked about her flow I realized mine was much heavier. I guess it just got a little heavier over the years so I didn't really notice.
I fixed the iron (well, am still fixing it!) mostly be cooking on cast iron, but also a little supplementation too.
No clue on the B12 and testosterone though.
Zone diet on and off for several years....worked, but too much focus on exact meal composition
Primal since July 2010...skinniest I've ever been and the least stressed about food