Queue Times

For about the past week, as a Silver 3 player, I have been getting 9+ minute queue times and end up playing with plat players. I don't know why this is happening, before the longest queue times I've had were maybe 5 minutes if it was at a rather odd time to play. But even during the busy hours my queue times, as a very average player where most people are skill wise, I have to wait a ridiculous amount of time. Why is this even an issue? Did Riot change the matchmaking again without telling us?