slow to enter a game

i used to be able to pride myself on always being the first one to reach 100% in the loading screen. one day, that all changed. i started to not only be the last to reach 100%, but because of me, my team will be on the loading screen for at least 5 minutes. either than or the game starts without me and by the time i enter, everyone's level 3. i click on the little "riot" thing and a window pops up and it says "game still in progress" and their is no reconnect button (WTH?). do not say that it's my internet connection, please. everything else on my computer runs smooth and during games, there isn't a hint of lag, but during that specific part, it gets weird.

this is a problem that recently just happened, and it's annoying. because of this, i'm condemned to playing bot games for fear that this problem may ruin a pvp game. i looked at some forums and apparently i'm not the only one who has this problem. unfortunately, their hasn't been given any answers besides "re install" well i wasted a couple hours doing that and it didn't work. the fortunate part though, is none of the threads about this that I've seen has been posted past 2013, so maybe 2 years have passed and a solution was found? :D

if anyone can lend me a helping hand with this and give me a solution, that'd be fantastic. this is pretty much the only game that i play, so i don't want to be screwed over by this problem.