Broke 4K and now I'm getting smoked

I broke 4K at the very end of last season and I won one match just to get the chest at the end of this one. I have only played dubz since then because I don't really feel like falling out of the threshold, but the amount of level 12 towers/maxed commons teams I've faced is insane! (I'm a level 10) and I feel really underleveled now lol.