Why Eliza couldn't sleep the past 2 days

Yes, I'm rationalizing.

So why?
1. She is getting sick. Today during our day out, she was coughing. Not the deliberate coughing out some sounds but it sounded like she was trying to get stuff out of her throat. And after her nap, she sounded hoarse, i could clearly hear the phelgm. Here we go again...sick Eliza. Why oh why??
Now how did she get sick? Did someone pass it to her? Did she not drink enough water? Was it because she was out in the sun (seemingly suggested by my mil)? Was it cos she was heaty, esp eating all the snacks?

I'm praying Eliza gets well soon. It's not fun being sick.