Feeling or exhibiting nervous tension
Be aware of how much caffeine you are ingesting; too much can make you feel jittery.
Rhyn asked, the feeling of doom making him jittery.
White sugar may also produce jittery feelings from the rise and fall of blood glucose and insulin that mimic panic attacks.
It is also possible for people with GAD to feel shaky or jittery.
Mental signs: Meth users may appear jittery or energetic.