Dealing with Chronic Pain and Unexpected Phone Calls

I was having such a good day yesterday with my trip to neuro, and hope for helping the pain I've had for years, always thought it was my ear, or neck, I guess I have nerve damage.. we are gunna do steroid shots in my head....then I was an idiot and answered my phone for number that is not in my phone, debt collector for a vehicle repo. totally ruined my day damn near had a panic attack and then forgot to go to the last food pantry of the week cuz they rocked my world in a 15 min. phone call... does anyone have any advice on how to keep it together when the tiniest things can just disrupt your whole mind/day?