I wish I could provide and answer to you, and myself.
Am sure another commenter can explain but "dread" is a good word for how I also feel but it's mixed up with anxiety/depression/phobias/fear etc. In my humble opinion, dread of going to the dentist for a filling, to me, is different from dread of having to phone and make an appointment to get my hair cut (new hairdresser will he/she come to house etc. etc. i.e. "worry" ?.
Not sure if this makes sense but I have generalized anxiety on top of numerous illnesses not a good mix... but when my physical ailments are giving me a rest, my anxiety/dread/worrying about "everything" is not so heavy: just doesn't last! Am curious to read the comments..... Best wishes to you, J.