Taking propranolol

In class whenever we do group discussion, i pray the teacher doesnt call on me. My heart beats rapidly and my hands, feet and arms enter a cold sweat whilst also shaking, feeling nausaue and sick; Then when i do speak my voice is shaky (sounds like im about to cry) and can only get 3 words out before i need to take a deep breath in while the entire class seems to find it hilarious. I've tried countless things to stop this but nothing seems to work.

Yesterday, while getting food i noticed propranol 40mg tablets and i really want to take it to get out of this horrible and embarrasing state of anxiety.

Anyone know the potential side effects to taking this without being prescribed it.