going through that with my mom was (and continues to be) the most difficult & devastating experience of my life (and it's been over four years now)
i lost a lot of weight too (almost twice as much as you--but it was across the first six months or so) because i couldn't eat. i bitterly referred to it as the death diet. be careful with that. i eventually ended up in the i.c.u. for four days needing a blood transfusion because of a bleeding ulcer i developed (from the stress, a lot of coffee, and occasional advil.)
i saw your other post about about sleeping and i remember, in those first months, waking up and then seconds later (when i'd realize she wasn't here) i'd burst into tears; feet not yet on the floor, head still on pillow, covers still on, and i was starting off another day feeling so utterly devastated. i still don't sleep for long periods of time but those morning tears don't happen anymore. (at this point in time my emotional floodgates don't open until late afternoon, evening, or late at night before bed. and not every day either. although last night i probably spent close to two hours in an emotional tailspin--and today my eyes are terribly swollen as a result.)
professional counseling or grief groups may have helped me but i never went (for several complicated reasons). but it might be something you can consider.
i hope you take care of yourself. 
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