OK, I'm going to offer my 2 cents as well since I consider myself very well researched in this area and feel I can probably be of some help. As for my background, I've been smoking fairly heavily for the past 10 years or so with the past 5-6 yrs being very heavy use (just about everyday). I started getting panic attacks about 2.5 yrs ago and I'm almost certain it is due to my mj use. At first they were subtle "weird" feelings that I would get at times after smoking a lot at once, gradually increasing in intensity until they were intolerable sessions of feeling detached, having a fear of fainting/dying, and feeling as though I were having a heart attack. I even ended up in the ER once while having a very heavy attack, but this was before I knew what was going on. At that time I still thought that something physical was going on. However, after much research and discussing, I learned that these were actual panic attacks via anxiety disorder.
The #1 thing to know is that panic attacks are just sensations (fear, paranoia, chest/head pain, etc) and nothing more. Your body is actually creating these sensations chemically, with the problem being that there is no actual real trigger or reasoning for these feelings. For example, if you were actually being chased by an attacker your body would produce a lot of adrenaline, restlessness, fear, etc while you were running. These emotions are there to aid you, in this case helping you to realize danger and flee. For someone experiencing a panic attack, your body is producing these same sensations but without a rational trigger. In other words, for some reason your body is incorrectly producing sensations as a response to an irrational stress trigger i.e. marijuana, getting angry, etc. That's all it is, a feeling - you're not in any sort of physical harm. After I knew this I was able to manage these panic attacks. Since my ER visit I've had ones that were much more powerful but was able to deal with it myself. Don't get me wrong, they are still VERY unpleasant to go through but at least you can be comforted in the fact that you're not really having a heart attack or about to die.
Lastly, just some stuff to add: (1) I've noticed that both sativas and indicas cause panic attacks. I think some people here said that you're ok with indicas but I've had really intense attacks after smoking indicas and sativas alike. (2) I've noticed that panic attacks occur when I smoke a lot at once, but not necessarily the number of hits I take. If I take a huge hit and it's a little too much I can tell right away that I will spiral into a panic attack. I would tend to stay away from bigger hits if you want to avoid a panic attack. (3) Like I said before, I'm almost positive that my panic attacks were a result of my weed use. Really think about whether smoking is worth the risk. For me, I can handle them because I know what is going on and can calm myself down (nowadays I'll have an attack about once per week, some strong and some weaker). But I can see how others may not be able to cope with these strange feelings as well. At this point panic attacks won't stop me from smoking but if I could go back 5-6 years I would have probably toned it down a bit so I never even got these in the first place.
Good luck!!!!