Congrats on day 3!
It takes time and to be honest I still get small episodes of fatigue. Not bad but just enough that when I get them I make sure I get extra sleep at night. There is nothing wrong with turning in early.
It was hard for me to work at first but as more days went on it got easier. I had a clear head so it I did not seem so dragged down by work. Get yourself some hard candy or chocolate. It helps. Alcohol had a lot of sugar in it and my body craved it. It gave me the boost I needed.
Take it easy and take it one day at a time.