Don't know about the working out thing. But I used have had low hemoglobin. During preganacy it's gotten too low - been fatigued. I did the iron pots, supplements, meats. The only thing that finally made my hemoglobin budge was a half of a liverwurst sandwich each day. kind of weird. But 8 seems pretty low. are you losing blood somewhere? Heavy periods, ulcer?
As I've gotten older my periods have gotten much shorter, now my labs are fine. I'm all about soy too, can't really imagine that adults are supposed to be drinking the milk of other mammals. But maybe you're getting too much. I have a serving or two without any problem. I'm thinking you just need to keep experimenting with diet, pans, etc.
Sounds like you're on the right track.