Falling backwards

I smoked the other day and went out to a restaurant with a buddy. The whole time we were there I was experiencing a powerful sensation of falling backwards. It was almost uncomfortable. A couple times I actually grabbed the table to "stabilize" myself. I've smoked a lot of weed, but I have never had this sensation, at least one this powerful, before. Anyone else ever experience this?

i get that when i smoke than go inside and sit down or lay down sometimes

did u feel lightheaded? Lack of oxygen to brain?