<human>: Could you distill the essence of the text into 1-3 sentences?

I've had a number of menial jobs over the years. My last one was working in a post room. I worked there for 4months and although I was eager to leave eventually I grew to really enjoy it. This new position is in IT, I got it through and internal restructuring. It's  a lot better paid, but literally from Day 1 I've hated it. It's only day 3 now and I feel awful, anxious and brutally depressed 

Is it too early to ask for my old job back? I know people will stay to stick it out. But I'm struggling to finish the week at this point, let alone any longer. Thing is, I don't really know exactly why I hate it, I just do! I know there is another internal vacancy in HR which was my 2nd choice before. Should I ask about that?
<bot>: I hate my new, well paid, professional job. I want to go back to my old one! Is it unreasonable?