worried about going into work

im at university and ive got a job transfer.
i properly start tomorrow (ive worked there once before).
i should of turned up last saturday but i had no idea i had to be there, well that's a lie, i knew i was working but they didn't ring me so i assumed i wasn't working.
they rang me around half 10 last saturday and i was very hungover and tired so i ignored the phone call. they rang me on thrusday demanding an explanation to why i hadn't turned up to work.

i just said i didn't know i was working and they really didn't take it well and i think theyre going be asking me questions tomorrow.

i know its my stupid fault.

i hate confrontation and this is surely a really bad start and im depressed and unhappy about it.

i cant sleep, literally cant sleep. im worried sick.

i'm a confident person so it hurts me even more when something like this puts me down so much.

agrh i know it sounds silly, i know but my confidence gets dented very easily.

like sometimes i can literally panic and not turn into work becaus eim scared of something.... who knows what im scared of. i dont understand my self.

sorry if im rambling.