Something somewhat similar did happen to me a few months ago but, it was just a few sentences. A fictional character whom I admire suddenly started speaking to me in my mind one day about how important it was that I eat healthy food and exercise because of my poor physical conditions. It didn't last long and I never hear disembodied voices unless you want to count my alters as I have DID. I do talk with my alters in my mind because we're all very close save for one or two but, that's another story. But, the voice that was giving me health advice could have had to do with the stress I was under also.