This program will help, do use it, until then perhaps like many of us, your associating the gym and panic together, because of the workouts it is normal to feel more out of breath, etc, and panic just magnifys any symptoms we get as panic itself,and that is all it takes to turn it into a panic attack.
Speaking that you need to take your boyfriend with you speaks common among us as the safe person. Even though in our minds we not they dont not possess magical powers from the panic, yet they do give us such comfort that it does seem to help keep the panic at bay.
To be sure, have you tried going to the gym, ONLY to observe for about 10 mins alone, not to exercise?
If you find yourself apprendensive going there alone, its the association with the gym and panic alone not the workouts. If you are fine, comfortable, can walk around for 10 mins, completely relaxed just watching, etc. then it is definitely the workouts themselves.
Let us know how it goes
Trish