I had this, for me last year i got really stressed about things then when i went to school i started to have a panic attack, then i started to get them quite alot after that. I went to see this lady in my school and helped me get through it, basically she tells you that panic attacks dont harm you, they are natural and your mind controls it.

Just try and forget about the whole thing about it, thats what i do (even though i still get some sometimes).