I am in a similar situation as you are, Anglynn. I did a 21 day Water Fast in April-May this year. I had to work and I found it quite hard. First week I took two sick days and the last week I used my one week vacation. It's not just about the smell of food because it didn't bother me after first 3-4 days. It's more of a mental fatigue from talking to people, looking at the computer screen, concentrating on work or study like in your case. I didn't feel like lying down so much, but I felt like being alone. And that's what we should be doing according to the laws of natural hygiene during an extended fast. Nevertheless, I am glad I fasted and I lost 25 lbs.
Anyway, I feel like I am ready to fast again. Today I stayed on water until 3:30pm then I came home and I had something to eat. I am planning to try again tomorrow. The first three days are the hardest for me too. Last time when I was about to quit on a second day people on the forum gave me support and strength to continue.
I am not sure about stress and fasting. I had to drive while on the fast and during stressful moments on the road I felt more vulnerable and sensitive than usual, and I felt immediate weakness after. Stress also causes acidic reactions in the body and thus interferes with cleansing. So, be careful.
Hope my experience was helpful. Good luck with your fast. Julia