“What is wrong with me?”

For the past 6 years, I have been sleeping a lot. As the years went by it got worst, I sleep all the time, it's annoying because I have things to do but my sleeping takes over, I have zero control of it and I feel very tired. I feel like my chest is closing in, like if I can't breathe. My entire body feels like it's about to dropdown. Also every time I laugh or in the middle of a conversation I feel a sudden weakness and my body literally drops for itself, this is something recent of this year. If I don't force myself with the little force over my own body I would sleep the whole day. I cannot function properly, it's uncomfortable and very worrying. Please help me. Thank You!