Loged into my world and can go throght anything in gamemode creative

So I log into my world and I start falling through the ground and I can see the blocks bellow me I start flying because im in creative and I try to go on the ground again but im still going through the floor so I thought it might be an elytra glitch so I take it off but it still did not help also I cant place or break blocks its basically like im in game mode spec but I have the creative inventory 2 min later I re started my game and entered the world it now works but this should be checked out also now im no pro game coder but from my knowledge it was a lot like when chunks don't load and you enter an un loaded one and you float through it but I could still see the stuff in the chunk.