I don't believe you were "possessed".. Due to my religion( it not christain, I'll just put it that way, if you curious feel free to pm me) But I can't say for sure if you were or not. I'm not an expert.
But I went through that while I was strap not in a hopsital bed it was because I went into deep depression and was so upset I somewhat lost my reason to think. I Obviously had saw or were thinking of something that made me extermly upset... And I got so deep into think about it, I blacked out.. or my brain did. And my body went into some sort of convulsion.. started screaming jebrish according to the nurse. But I'm not expert sooo... It could of been anything.