I have an 8 year old female house cat.  Her last checkup was in
September and she received a clean bill of health.

Since she normally wakes us up way to early in the morning, we have one
of those feeding dishes which opens on a timer.

We were at a super bowl party on Sunday so I set the timer for her
evening feeding as well (she is fed twice per day and is only fed a
total of one-third a cup of dry food per day).  When we got home on
Sunday night, her food was only half eaten (normally all gone within an
hour or so) and I threw the remainder out when I went to bed.

Monday morning when I awoke she had again only eaten half her food and
thrown up (not at all a common occurrence for her even during the
months she is shedding).  I put some laxatone in her dish (which she
normally loves) and she wouldn't eat it.

Last night she only ate half her food again at the evening feeding.
This morning same thing and she again refused the laxatone.

She has been going to the litter box (#1 and #2) with no real problems.

She loves cat grass and while we haven't given it to her for a while
she bought it again at Christmas so she's been eating it daily since
about then.

I don't know if she is sick or if the grass has created an obstruction
or if she is just getting older and not in the mood to eat as much.  My
concern is that the change in eating occurred so quickly and
accompanied her throwing up.  We have made no changes in her diet or
feeding schedule.

Anyone have any ideas?  Think this requires a vet visit?  Possible
obstruction??