Hi superanon girl. It's possible you're just experiencing transition symptoms and you'll get more energy as the fast progresses. Many people can fast while continuing to work but many also cannot. If your body needs more rest than you are able to provide it while still working then you need to decide whether you can take sick day(s) or if you will have to end the fast early. If you end it properly with raw foods then you will maximise the benefits of the fast and make the next one a lot easier as a rule. So even if you can't continue working this time it doesn't mean you won't be able to next time.