Move Problem

I just started to play a game. As soon as I made my first move, (just outside the shop), my champ (Kayle) started moving straight towards the enemy nexus, right up the middle lane. It look as if I had right-clicked on the mini map (when I hadn't!)

I obviously died once I walked past the first tower. Mouse was working fine... except that it wouldn't let me move my champ...

Once I died I respawned and right clicked, again just outside the shop. Again, the champ started straight towards the nexus and I died again.

I exited the game and reconnected. Things worked fine for the rest of the game. Nots ure what the problem is but thought I should post in case others are experiencing the same thing.