When I was on P1 last year, I also got strep throat. I made the chocolate drink (powder) hot and had it as hot chocolate. I also made my own chicken soup broth.
Take any kind of chicken that is on the bone. Put it in a big soup pot and cover chicken with water. Boil chicken for about 1 hour. Remove chicken from broth and let cool. While chicken is cooling, put broth back on heat and add leeks and celery. Add in some spices and salt & pepper and sprinkle in a bit of tumeric to get that yellow coloring. Once chicken is cool enough to handle, start removing the meat from the bone and adding back into the stock. Let boil for another 1-2 hours.
Even if you can't manage to eat the pieces of chicken, you can easily sip the broth. This should help keep you on track, keep you in ketosis and shouldn't do any damage.
The thing that I noticed the most when I was sick was lack of desire to eat veggies. So I just didn't eat them. I stuck to the soup (above) and the chocolate drink warmed up. I think I lost (3) pounds that week.