Ahem time to become a nerd heh... Like the person that replied below it's something common but it should NOT be ignored, shaking can be caused by Anxiety, stress, caffeine, low blood sugar, medication side effects, alcohol withdrawal, thyroid imbalance. Which you I know you have 4 of the things on the list (4 maybe 5 don't remember) so it will and is probably led to all that. I would recommend doing the things I'm about to say and if not go to doctor soon, but some things that might help is Avoiding excess caffeine and limiting alcohol may help reduce a tremor. Using relaxation techniques, such as massage and meditation, and doing tasks differently, Wear a heavy bracelet or watch. And avoid intense exercise and heat.

Well Shaking can be a response to Anxiety, it mostly occurs when you're in a middle of attention or something that makes you extremely nervous, but shaking because of anxiety is serious sometimes it just occurs even if you're not nervous. It's common but it's not something you can ignore