Battlefield 3 Premium guns lost

If this is your battlelog profile:  http://battlelog.battlefield.com/bf3/soldier/Boofhead35/weapons/334589017/xbox/ then you should definitely have access to the expansion weapons except for te L85A2 which you haven't earned yet.  Also I see that you don't have the physical warfare pack, that is a free download on the Xbox Live Marketplace that gives you acces to the Type 88 LMG and some additional items for the SKS and DAO12.  One more question, can you join matches on the expansions since losing access to the expansion weapons?

Since you should have access to the weapons but don't I recommend that you re-download the expansions in case they've been corrupted during an update which happens frequently.  To do this you will have to go to your purchase download history, since you're on your computer it's easiest to log into the Xbox Live site at http://www.xbox.com/en-US/ and then go to "My Account" and then "Purchase History" and then scroll down until you see your online pass, your premium file, and the expansion packs and click "Add to Queue" and then the next time you log into your Xbox your queued items will automatically download to your Xbox.

After all 5 expansions completely download (this could take a while since each expansion is about 2 GB) start BF3.  At the main menu you will receive a series of pop ups stating that you now have each expansion.  Now from the main menu go to multiplayer, open server browser and then open the server browser filter by clicking R3 and check all new maps and game modes or you won't find any games on the new expansions.