As for doing activities with dogs...how wonderful!
Body for life works for me because it's a challenge and I feel like I'm a tough bodybuilder. That's what keeps me coming back.
I can see that doing activities with your puppies is tons of fun for you...so that is most likely the best exercise for you!
I'm so excited for you...getting out and trying new things.
As for the fatigue...have you gone to the doctor, gotten your thyroid checked? Eliminated other physical things?
It could be just you needing to take some time and greive..but I'd hate to think that you were battling something physical on top of the emotional...make sense?