After drinking a lot of soft drinks i get really sick; nauseous, shakes, heavy heart beat, dry mouth and anxious. it last 1 hour. very worrying?

Caffien and sugar: Most of soft drinks have caffien and sugar, what you are going through is a stimulating effect and increase in your blood sugar which can cause increase in anxiety and restlessness. It is mimicing a panic attack. Go easy of soft drinks, you will be alright.

Stop drinking soda: I recommend stop drinking soft drinks: they are not good for you anyways. Then call your physician for an exam. You might have a reaction to something in the soda, quite possibly related to the sugar or the sugar substitute if it's diet soda.

No More: No more carbonates soft drinks, but i would keep some type of journal and record if you get any of these symptoms with other foods or beverages. May not just be from soft drinks.