Is the save option grayed out? Did you happen to switch profiles on your Xbox?
I lost my saves as well. They all attempt to load, but crash to dashboard! I've found a few others on here reaching out with same issues but no replies. I was lvl 22 with 34 hours in. Had 4 or 5 autosaves and a quick save within a minute of each other and they all crash when trying to load.
I was 18hrs in and I went back to play, I recieved a error saying saved games could not be loaded go to offline mode, now my load bar is grayed out, any ideas how to fix this?