I feel like I'm dying when I smoke weed.?

Ok, first of all I've only smoked weed once. This was back when I was 12, I'm currently 18. Now, when I smoked weed for the first time, I went into it with no fears and good intentions. I took 6 strong hits from a blunt and then got horrible cottonmouth. Put it this way, I was so high that I started breathing like an idiot. I was inhaling and swalloing the air. XD. I then got really scared and got super tired after about 30 minutes and ped out. After that, I had panic attacks for months and felt like I was dying. I'm considering trying again by myself. Maybe just one hit and see what happens. I have certain allergies so I'm concerned that might be it. If so, I'm disapointed. I would like to smoke because it helps with sleep and relaxation when done right but I want a couple legitimate opinions.