cat eating timothy hay = vomiting

I am concerned about my kitty and am considering another trip to the
vet. She was seen a week and a half ago and had some xrays done. They
showed an obstruction that was clearing up with some pepcid and a
little more vomiting (after a few days of it culminating in a refusal
to eat and emergency action). Her blood tests came back with no
worries and the illness cleared up with some pepcid and antibiotics at
home. Now she is once again not seeming to keep anything down. I've
just given her some more hairball remedy on a truly empty stomach.
There is also a rabbit in the household and I suspected the previous
obstruction was due to hay. At this point I am convinced that is the
problem and would like to avoid the ill-timed financial burden of
another trip to the vets office if there is something that can be done
at home. Obviously attempts have been made to keep the hay out of her
reach and just today I say her stroll over to the part of the rabbit
cage where the hay used to be kept. Thus my firm idea that it is hay
that is causing the problem. (she has been sick with hay in evidence,
previously)
Anyone have experience with this? Will she be okay or should I take
her back to the vet? I plan to call tomorrow and ask my vet, but I
would also like some over the counter advice, some experience with a
similar situation.

thank you