Sometimes I'll be laying down or just sitting on my bed and I feel stuck... Like I can't move.…

Sometimes I'll be laying down or just sitting on my bed and I feel stuck... Like I can't move. Anyone else feel like this? Doctors say I'm fine lol I think it might be anxiety in a different way. I've had anxiety since I was 13 and I'm 19 now. Should I be concerned? I may sound crazy right now but it's like my body starts to feel heavy and I just don't want to move. Not sure if I'm just tired or its all in my head...