Recently, most nights, i have been experiencing palpitations and internal shaking. so much so, it keeps me awake for hours. what is happening?

Possible anxiety: Unless you suffer of any specific illness at your age it is most likely that anxiety is causing your symptoms. However it is always wise to get evaluated and if it is something persistent get tested for other problems. Other possible reasons are thyroid, elevated blood sugar , cardiac arrhythmias among others.

Palpitations: Do you experience palpitations during the day? Do you know what your pulse rate is during the palpitations? If you only experience palpitations when in bed and your pulse rate is less than 100, anxiety may be the cause making the heart beat forceful instead of rapid. Avoid caffeine and alcohol in the evening. See your physician for further evaluation.