Yep, you had a classic panic, or anxiety, attack. They are usually an unconcious response to something bothering you. Not that you're unconcious when it happens, but you're not actively thinking about it. Weed can definitely trigger these or make them worse. You were probably stressed about the possible drug test when you smoked so your body reacted the way it did. Now, you're so worried it might happen again just the smell starts to trigger it. The good news is that knowing what they are and why they happen often makes them stop.