Big problem : missing textures, missing sound, long loadings...

Hi there !

I've been looking through searches after searches with dozens of different keywords and I just can't find how to solve my problem...

Here it is : I just bought Dragon Age Inquisition a few days ago. I've played a dozen hours and everything was fine.
And then, out of nowhere, the game started to look awful. Here are a few problems I'm experiencing and have no clues as to why the f- they appeared:

- Most textures on objects in the decor (intracting ones or decorations), stones, walls, clothes, ground seems to have gone to oblivion, as if nothing charged fully and I'm left with square-looking things out of a very low quality Minecraft game. You can see on the link below what it looks like. And sometimes it's even worse. Notice how this guard's armor on the left is fully detailed whereas my almost all other clothes look like mushed polygons.
http://imgur.com/9dEkJvg

- Sometime I launch my saved game and my character appears in the map and I can't move and only half the things are load on the map, like if I pop in the Throne at the QG, behind me throne, statues, half the wall would be invisible and I'm stuck and can't move. I relaunch the game and I then can move.

- I walk around as usual in a map and BAM, all my characters freeze mid-step and I can't do anything except open menus and such. Fast travel at this point just led to a never ending load screen or if it loads to the nearest camp, characters are still stuck.

- Very looong loading screens between fast travel point on the same map, passing a door in the QG, etc.

- Sometime during cutscenes with characters where you will have to talk, they end their sentence and then stay stuck there and the conversation will never continue as if not done charging.

- Sounds are missing while in battle, which feel very weird when a few days prior I was amazed at how precise the stereo sounding was when there was fire, you would hear it either on your right or left depending on where it was on the screen etc, and now, I have battle with half the sound missing and my characters are launching attack that doesn't make sounds half the time.

- When in menus, either inventory or craft menus or menus to personalize QG, nothing appear where you should have your Character or items showing on the right side. In QG personalization menu, small pictures on the right stay stuck with a loading icon and never appear, in other menu, characters just never show up.

- oh, and today, Solas disappeared. He's there, he's still casting spell and everything, he just turned to invisible man. I have to give him a torch to hold just to know where he is outside of battle.

- All this only occurs in solo game as multi appear to have perfect graphics and sounds and no problem with connection or loadings or anything.

I think this is all I can muster up for now. All in all, it seems my game just won't charge half of its content, which I don't understand...

Things I've tried :

- in game, changing all graphisms settings in options to low, high, ultra, whatever.
- uninstall, reinstall
- repair the game
- trying with connection to origin and without it.
- changing windowed mode (which i'm used to play with) to full screen did appear to change something as I suddenly had my game working to its fullest and with perfect graphisms and then i had to close and relaunch and everything was back to awful.
- updating pilots (they are all up to date)
- in option games I can switch between direct3D 11 and AMD mantle and it changes nothing (i don't even know what is mantle)
- asking my bf what the f- is wrong with my game (told me to put full screen then now he doesn't know anymore)

- downloaded AMD Gaming Evolved which supposedly boost games but it does nothing.
- go through every analisis : virus, malware, scan disk...

- playing with antivirus deactivated

- closing everything on my computer (I usually only play with youtube and TeamSpeak running in the background)
- searching for hours on google and diverse forums.
- crying in rage.

I'm stuck and it's really horrible to play the game. I was so into it and now it's just unpleasant to even launch the thing because I know its going to get stuck somewhere and I won't have access to all the features or I will lost so much time in loading screens or whatever...

If soemone has any ideas, I'm taking them and sending you cookies. Also, sorry for typo, grammar and everything !