Can you change your ringtone to something that alerts you that you're not familiar with? I change my ringtone frequently because I hear it "ring" too, and I find that when I change it I hear the old ring for a while and when the new ringtone comes on I can differentiate it from a hallucination. I don't get a lot of phone calls so it takes a week or two before I get used to the new noise.

That might at least help you out to answer your pdoc's call. Hopefully your doc will help you out med-wise to reduce your overall symptoms. Until then, practice distress tolerance skills/coping skills, self-care (the basics like getting in some nutrients, bathing, brushing your teeth, etc), and reality testing.

I find cold things help. Rubbing my arms with ice, dunking my head in a bucket of ice water, or taking a quick cold shower. Deep breathing calms people down too. Try and keep yourself busy with any healthy activity, try and get something that keeps yourself physically busy and get something that keeps your mind busy in every day (I like to garden and use duolingo to learn other languages right now). Look up some grounding techniques online and try them out to see which ones work for you.

And finally, remind yourself that you've been here before and gotten through the other side in tact.