Sleep paralysis... Wtf just happened to me.

So I was sleeping last night. My fiancé left for work at apprx 330am and I fell easily back asleep. I believe it was around 430am a sound in my ears/Brain woke me up. It was like a high pitch, then a fuzzy dead tv sound.  I opened my eyes only to not be able to move.. Not even a muscle. It only lasted about 30 seconds max but I couldn't help but freak a little. I'm not much of a "spirit science" kind of girl but once I could move I felt weird in my room, like maybe something was there. What just happened to me?!?!?!