Panic attack In sleep?

Lately I've Been falling asleep, And As I fall asleep Im kind of awake, but then I feel my heart rapidly beating and I feel as if I can't breathe and then Im totally awake and my heart rate slows down to normal.

The weird thing is im 18 and not overweight.  Anyone experienced this at a young age?  I Know some answers will consist of getting professional help, But I just want general knowledge right now.

Could you possibly be having night terror? http://www.nightterrors.org/ My husband has these and he's had a number of the things on the sight happen to him.  They can be really scary the few times it happens. Sad to say I've gotten used to them by now and barely wake up anymore.

OMG...growing up, I had terrible spurts of anxiety at bed times.  I talked to a doctor and she suggested getting a music box that played a song that I could lay there and sing along to.  When you start too feel that way, turn on your music box and just lay there focusing on the music and taking nice slow deep breaths.  I'll tell you....I don't know what I would have done with out my clown that played "It's a small world"!!!!

I used to wake up with panic attacks for months a few years ago (I'm 21 now). I would suddenly bolt upright and feel myself pouring with sweat, shaking, feeling sick and my heart pounding. It was right when I moved into university halls and was really stressed and nervous after moving away from home. If you have any issues which might be making you stressed try and talk it out with family, that helped me. If not, then I hav no idea!

Try googling sleep paralysis. It sounds like you may be experiencing a mild form of it. Basically its a state between asleep and awake. Like your body is asleep, but you are conscious. It is often paired with a lot of anxiety/fear and occasionally hallucinations.

I had severe SP for a long time, but learned to control it with lucid dreaming.

Hope that helps. 

Definitely sounds like sleep paralysis. 

Although this is probably one of the most terrifying experiences one can have (you feel like you're dying at the time), it's really nothing to worry about healthwise or weightwise.  It occurs most frequently in people who are experiencing stress and/or frequently sleep on their back.  Sleeping on your side or on your stomach might help.  The important thing is to be aware at the time that this is what's happening and that it will pass in about 30 seconds.

You might Google "Sleep Apnea" too.

Have you had your thyroid levels checked? Sorry, but the only experience I have had with things like that was thyroid issues so I always tell peaple to get it checked. I think everyone should get a simple TSH blood test once a year no matter what the age. Stress is a another factor too. Best to you!