djh, I hear you on the fatigue though I wasn't experiencing the mood swings so badly... mine was just debilitating fatigue/exhaustion/sleepiness and I struggled desperately to figure out what was going on until reading some of the posts here I realized it was part of MS. I just never connected the dots to the "debilitating fatigue" of MS part for some silly reason... but suddenly it made sense as to why I seemed to be experiencing practically narcolepsy in the afternoons!
With that I talked to my PCP and then my neuro who agreed, and both put me on Provigil which has been my godsend. I take 200mg daily. I still experience some sleepiness depending on the days activities and I still experience the fatigue to some degree but not nearly as bad, and I can get thru a day without practically falling out of my chair asleep!
Exercise is great too, but at the same time, it also causes pain for me. So I have had to find a balance on it all, the provigil though has been wonderful! My insurance company fought both drs for the prescription reasons to order it but have finally approved it (thank goodness as it's $1250/mo) and now all is good!