Analogy:
I have a real bad case of bronchitis...and I have accepted the invitation to go to bf for the weekend...which is in five days...depending on how I feel each day will make a difference in how I view the weekend. By Friday I may know, or wait until the last minute on saturday.
A lot of the feelings are the same:
do I feel I have enough energy?
do I even want to deal with this person today?
or do I want to sleep?
what will the effect on me be if I go to his place?
How long an effect?
ETC.

Now, I got sick over the holdiay weekend and week...same as the thing I had in may...fever, lungs, throat, etc...losing voice this time round.
I was supposed to go to bf on friday, my worknight...didn't just felt too icky...then didn't go in to work(or bf) on sat sun or mon. On top of that we were going to watch fireworks on the fourth...I knew he would be disapointed, and I knew it would probably kill me to do so in the cold wind with firework stuff in the air, asthma. So, we stayed home...tue and wed are our weekend...so stayed home wed, too...great way to spend the 4th...in bed sick...ok, so he was company...but, didn't help how I felt.
It took me 40 years to realize Dad was right about some things...one being if I am sick...stay in bed...or it will become worse...I have not been as sick as I have been this last year, ever in my life...and hope I get passed it soon.