Sentence 1: Rena has a hard time falling asleep. 
 Sentence 3: But the sleep doesn't last very long 
 Sentence 4:  She wakes up multiple times throughout the night 
 Sentence 5:  The Doctor has told her that she has chronic insomnia 
 Option 1: She took a sleeping pill and slept for 8 hours. 
 Option 2: Sometimes she gets lucky and falls asleep within 30 minutes.