The medical causes needs to be ruled out like low
blood sugar, hyperthyroid state, cardiac abnormality etc. You should quit coffee, smoking, tea, alcohol, heavy meal which can trigger blood pressure and cardiac load leading to palpitations. Get an ECG to rule out any heart condition, blood sugar, thyroid status. If any medical condition found, should be treated accordingly.
Reduce weight if overweight. You need to share your problems with someone close.