Good for you for not giving up! The best thing I have learned about this is that when you have a panic attack, we tend to associate that situation with panic and then we tend to either panic during that situation or avoid the situation all together. The only way to get away from that is by forcing yourself to be in the situation and keep forcing yourself into that situation until the panic caused by that situation goes away. This is difficult and may take time and may take doing more than once, but it really is the only way of beating it. Let the panic come, make yourself stay in the situation, reassure yourself with positive self talk that you can do it and that your feelings are only coming from anxiety, and by doing this, you will prove to yourself there is nothing to fear. Like I said, it may take some time and it may take doing more than once or even ten times - but keep doing it. Prove to yourself there is nothing to fear and you will beat it.
I have also learned that after conquering one fear, another often comes up in a different situation. But, the formula to beating it is always the same. Keep at it and prove to yourself there is nothing to fear!