Wrong game speed.

Playing as Lucian at around 25 minutes into the match I noticed I was moving way too slow for 400 movement speed. I was moving at around half that. All abilities (enemy champions,friendly champions and mine) were slowed down. I think only projectiles were the same speed. I was teleporting from time to time, maybe the server was trying to place me where others saw me or something. My Shaco was sliding around. I decided to restart the game. When reconnecting the game crashed, but i didn't send a report. On the second try, it loaded but the problem was still there. Only when the game ended at the final animation it was fixed. This has never happened to me before.