And back downhill again

I think I'm about 95% sure I'm pulling out of the 5K I'm supposed to run on Saturday morning.  I'm really disappointed by this.

While I feel a whole lot better than I did last week, I'm pretty sure I'm not recovered from my illness.  I'm still on antibiotics, of course, and am taking them faithfully.  I tried to put in 3.5 miles yesterday and got in 2.  This morning, I tried another two, and I was really struggling through the first mile.  I decided to stop after that.  I just couldn't get my legs to move.  I had absolutely no energy.

I don't know what it is.  I have read that after an illness, you shouldn't race for 2 weeks.  Maybe I should take that to heart and not run, rather than risk injuring myself.  Maybe it's just a side effect of the antibiotics.  Maybe it's my diet.  Since I've not been running, I'm not as hungry, so I've been eating a bit less.  Not an unsafe amount less, but probably around 1400 calories/day versus 1600 calories/day.  Maybe that's having an effect. 

The last thing I want to do is hurt myself or end up hating running.  But it is just so disheartening to not even be able to run a mile.  I'm scared I've lost all the ability that I've built up.  I realize that's really unlikely, but I'm still just really upset about this.