DCd, cannot reenter game

I was playing a solo ranked game as Thresh. Then all of a sudden I was starting to lag and it said "attempting to reconnect". After waiting a while, I just alt f4 so that I can just reenter the game. But when I did that, there was no option to reeneter. It just put me to the main screen, as if I was never in a game. What should I do? I can even queue up for another game, but I am almost in promos so I want to go back and help my team