It is an interesting and beautiful characteristic to see two cats that close
to each other. I've only seen it once and it that case, the smaller of the
two ie a female, was the one who had attached herself to an older Tom.  Then
one day, she disappeared (they were both visiting strays we fed ). The Tom
(who we now look after full-time) was not noticeabley effected,..so it can
be one-sided a bit.

Cats see us as other cats, or so I;ve read,..so on this basis I can only
state the obvious, which you're already doing,..extend your attention (if
time and life permits) to take-up some of the loss she feels. Fretting is  a
real phenomona amongst many animals. If you give her treats that you may
have noticed she likes, such as meat from your plate (our Fatso loves
cold-cuts or salad meats) or maybe fish-treats for example,..she may well
feel that extra attention and come to feel a little less depressed and
anxious.

Another thing I've noticed, is many cats love to sleep on beds. They almost
always like soft, fur-like dooners or quilts and in our Fasto's case, the
exposed mattress as its smooth and warm feeling. They purr and massage the
bed and seem to really appreciate this type of special contact with us.

Really hope she gets over her fretting,..a nd best of luck.

Jason

Pets have their own way of mourning.  They miss their housemates.  Have you
considered getting another cat?  I would go with a kitten.  It will take
Rosy to get used to the little hyper one, but it will happened.  I've found
with older cats that a kitten works better than an older shelter cat.  The
kitten has yet to form a solid personality, habits, etc.  An older cat would
bring with it habits and possibly a temperment that you and your older cat
would have to get used to.   Just my opinion.