Lost control of my character

Just happened, and I don't know if it will ever repeat (since the game is still going on), but I recently joined a ranked game. Pre game I was stuck at 100% at the loading screen until I joined in at like, 2 fps (which sometimes happens at the start before it evens out to like, 20 fps), at about 49 seconds in. After a bit of lag, I opened the shop and bought my items. I clicked on the botlane outer turret (I was support thresh), and the game read that as me going straight towards the enemy nexus. The game froze, when it unfroze I died and everyone was either angry or confused, I tried to explain, but when I tried clicking on the bot lane again it went towards the nexus again. Every time I tried clicking somewhere else it did nothing. Figured I'd let you guys know just incase anyone else has had this happen. Oh, and I don't have the best internet connection, tough I tend to get a ping that fluctuates around 80-140 while loading.