I believe that many people, including Sauron, believes that Elo brackets are in intervals of 100's. So, it is possible that your elo recently dropped an elo bracket so you are now going against lower level players. Such as, if you played Ranked Summoner's Rift, players in the 1100 elo generally play worse than the players in 1200 elo. Some people say that the difference is significant.
The opposite is also possible. Elo is really the probability of winning. Matchmaking tries to make it so each side has the same chance of winning. If you get higher elo, you will get matched with people of lower skills to keep the game even. If you were to play during the busy times, then you will probably just get matched with people around your own skill level. The longer matchmaking takes, its elo search range increases.
So, your best bet is to try to play during the busy times. If it really frustrates you, then go to DominateDominion and find some people to queue with.