Hi @KateM - I'm not sure which Chemo regime you're on? I felt really 'out of body' when I was on AC - especially after my first treatment. Now, on Taxol I don't get that anymore but the fatigue definitely lasts for a few days.
You'll probably find that things will start improving after days 5-7 and you can actually feel a lot better from one day to the next.
If you can, drinking lots of water as @JenniA suggests is a good idea and a lot of people say that exercise helps but I wasn't really exercising much before my treatment started so it wouldn't have worked for me to start during chemo.
Listen to what your body wants you to do - everyone is different. If you feel tired, rest; if you feel sleepy, sleep; if you're a walker and you want to get out in to the fresh air, go for it; and if you're craving any type of food - eat it!
Best of luck with it all!
xx