Yea, that exact (well not exact, different situation, same feelings and actions I guess) happened to me the first time I got high. The "sucking and muffled sound" in the ears, the trying to stay awake, everything you mentioned all happened to me. That was my first time getting high, and it freaked me out too. I still get it when I smoke a lot, and I enjoy it now. Hope it didn't scare you too bad