Depending on how long your break lasted - we had a full character wipe in September last year, some months ago we had a weapons wipe that removed all weapons with a slash of above 10, and earlier this month characters that were created after July 4th were also removed because of a bug/exploit.
If you think that these wouldn't quite fit into your time of absence, and you didn't share your account with anyone, the loss of items would have to be attributed to a bug..