I can't close my eyes for a second.
There's an old saying that if you think you're in danger, you might ought to sleep with one eye open. 跟咱们的"睁着一只眼睡觉"感觉很像。
还有一个表达,也是表示"时刻警惕着":
be on the lookout (for somebody or something)
to watch carefully for somebody or something in order to avoid danger, etc. 例如:
The public should be on the lookout for symptoms of the disease.
non-starter
A thing or a person that has no chance of success. 不可能成功的人或事,例如:
As a business proposition, it's a non-starter.