Panic attacks on Marijuana

I am not unfamiliar with panic attacks, when I was 10 I had one, but it was nothing like the ones I have had when I was under the influence of Marijuana. The first time it happened I was 12 years old, I was smoking out of a bong with two of my friends and the dad of one of them. I was eating a sandwich and my tongue started to feel weird and it felt like it was going to melt off. I looked at the three people with me, starting to think we were crazy, my body began to hurt and it felt like all the negative thoughts were rushing through my skin, I began to convulse and I couldnt breath, my heart hurt, my friends took my shirt off and layed me on their couch, I passed out. My mind was never the same again, I went through depression and everything wasnt as bright and wonderful as t use to be. I use to always be optimistic, now life is harsher than before.

Then a couple days ago I was smoking, and I knew I was good for the day, but then they brought out a five footer bong and I hit it, it took about 30 minutes, I was fine and everything was going well, but then I began to panic, for two hours I convulsed and cried out of pain, I dug my nails into the carpet and calmed myself down. I focused on my breathing and my heart rate, I thought I was going to die, I don't remember much and I freaked all my friends out. I couldn't believe how intense it was, but it was nothing new.

The tips I could give to others is this:

Breath
Don't worry about the things around you, whats important is for you to calm yourself
If you know you shouldnt take another hit, dont!
Its ok to lay down and let it out, dont be afraid to scream a little
Let yourself go and accept that you need to let it all out
Do not, do not leave where you are, even if you think your episode is over

I thought I was the only one who has gone through this, but sadly to say I am not. I hope you all survive and learned.