Tryn Damage Bug

So i was playing a game top vs mundo. I play tryn every day I know how much dmg he does. I went after mundo early game and was hitting for no damage. So I was like weird why is mundo doing so much more damage than me. Then I noticed I was hitting minions after I had gotten some items and I was doing no damage to minions either. For some reason SOMETHING happened that my damage was gone I had like 160AD and I was hitting regular minions for 20 damage late game. Everyone on my team and the enemy team all noticed it I couldn't do any damage. So something is wrong. this is the first time its happened to me and i play tryn every day. I was top vs a mundo and normally mundo is very easy for me to kill. And mundo was hitting like a truck while i was hitting for no damage even at level 1. It was like mundo and my stats somehow got swapped.