Game Crashes and Bugs

So I'm on dxun going to do the tomb of freedon nadd. When I get there I only have atton. also the madolorian mines detonator and droid and turret things are all invisible. Also when you load a game when you are outside the tomb it places you at tue bOttom to the right by the ship. And in the tomb always at the entrance of it but past where you go out so when you want to go deeper into the tomb you have to exit and then go back in. This happens regardless o where and when you save. So I went through the whole tomb with just atton twice because I tried loading an earlier save which didn't work but then when I talk to the mandolorian to cut to the other half of the party the game crashes. Please help me.