It could be too much caffeine but I would not mess around with this. I'd see your primary doctor to discuss this and they will most likely refer you to a neurologist. Twitches and anxiety happen but hand tremors seem more neurological. So, go talk to your doctor to get to the bottom of this. Let us know how it goes!
My mother had severe anxiety. After figuring out GERD was due to insufficient stomach acid (yep high acid is rarely the cause!) I took her off nexium and put her onto betaine HCL with pepsin supplements and digestive enzyme supplements. I also gave her sublingual B12 (her B12 levels were low due to low stomach acid).
Increasing her stomach acid and giving her more enzyme to digest her food and GERD went away but so did all her other health issues including anxiety (lack of nutrients from B vitamins to magnesium are noted causes of anxiety).
Her symptoms of low B12 included pins and needles and numbness. Vitamin B12 is essential for the myelin sheath that surrounds the nerves.
Magnesium is also called the anti-anxiety mineral.
Excerpt from Need More Magnesium? 10 Signs to Watch For...
"4. Do you drink coffee, tea, or other caffeinated drinks daily?
Magnesium levels are controlled in the body in large part by the kidneys, which filter and excrete excess magnesium and other minerals. But caffeine causes the kidneys to release extra magnesium regardless of body status.
If you drink caffeinated beverages such as coffee, tea and soda regularly, your risk for magnesium deficiency is increased."
talk to your doctor, I think you'll be referred to a neurologist. good luck and do come back and let us know how you are doing and what the doctor thinks might be the issue.