Minecraft starts modded but becomes vanilla when i open a world

[rex14rifle]

I HAVE NO IDEA what caused this butjust today i decided i wanted to playt some technic so i launched it said it needed to update i let it update then i went to play ftb infinity and it started and everything was working i played around for a little bit and then i noticed something: this is not at ALL what i saw on then internet so i opened to LAN and went to creative and sure enough there was no modded items so saved and quit and on the loading screen it was vanilla there was no mods  button forge seemed to have vanished THIS IS NOT A MODPACK BUG REPORT it happens every single modpack i have i dont know what to do anyone got any ideas?

[FriendlySurvival]

So it won't even shows the forge loading screen where it initialize the mods and so on? Furthermore what is displayed on your bottom left of your Minecraft main menu? 

[JaariAtmc]

This is a modpack bug report, and a bloody obvious one too. And its all about a crappy rehost of the FTB LAUNCHER modpack Infinity...