The phrase "snug as a bug in a rug" means to be in a warm and comfortable place, feeling protected and secure. However, there are several antonyms that describe a situation where someone is not comfortable or secure:
1. On edge: feeling tense, anxious, or nervous
2. Uneasy: feeling uncomfortable or uncertain
3. Exposed: not protected or covered, vulnerable
4. Unsettled: not fixed or stable, constantly changing or uncertain
5. Unsnug: feeling uncomfortable or not fitting properly
So, if you are looking for a way to describe a situation that is the opposite of "snug as a bug in a rug," you can use one of these antonyms to create contrast and convey a different feeling.