Panic, for one.
No, nervous and sluggish are not synonyms.
anxiousness, disquiet, panic
The word that means the opposite of nervous is "calm." While nervousness is characterized by anxiety and agitation, calmness reflects a state of tranquility and composure. Other synonyms for calm include relaxed and serene.
panicscaredworried
A term that can be used for a nervous fit is an "anxiety attack" or "panic attack." These are characterized by feelings of intense fear or panic, physical symptoms such as rapid heartbeat and sweating, as well as a sense of losing control. It is important to seek support and treatment if experiencing frequent anxiety or panic attacks.
Anxious or jittery can be synonyms for nervous.
Anxiety, uncertainty
affliction , anguish , anxiety
scared, frightened, nervous, terrified, shaken, startled, fearful, cowardly, reluctant.
anxiety, worry, unease, apprehension
nervous, antsy, edgy
fux, inconvenience, anxiety, trouble, problem