Insomnia
noun
The not sleep symptom shows you have a disorder that involves not sleeping. That is insomnia.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
彼と仕事をするのがストレスで、不眠症になってしまいました。
Working with him is so stressful that I got insomnia.