newbie here--still in shock

my mom just diagnosed with advanced abdominal fat pad cancer, ovarian primary. saw oncology first time yesterday. had undergone paracentesis 2 weeks ago good result and is feeling pretty good, eating good, but extreme fatigue. she is a diabetic and has had some fluctuations in blood sugar but now seems to have normalized. no pain as of yet, only mild discomfort. she is 97, declined chemo, on to palliative care after PET for a look see. i am her oldest, live 500 miles away, going to visit at her request "while she still feels good." i am a total basket case...have already alienated my brother and SIL, who is a nurse and as she says "a trained professional" like the rest of us are mental defectives. had her dead and buried 3 weeks ago, all gloom and doom. she has a tendency to overstep her role because of her "professional" status...i understand fully the situation and what the future likely holds, but my emotions and grief are overwhelming....looking for grief support, that's if i can put one foot in front of the other and stop sobbing...any advice?