Glad you are feeling a bit better. The lemon cordial might work for you.
Other things to try are drinking through a straw, drinking really cold water, drinking flat lemon or lime flavored mineral water or flat ginger ale.
I also found lemonade ice blocks or calypso ice blocks helped my throat to feel better and these added to the fluid intake.
Maybe you can get your sister to grab a few things for you to try. You will probably still feel very low energy for a couple of days and then start to improve.
Take care.
Deanne xx