The male rabbit should be kept away from the female for about 6 months after the operation untill he is completely clear. If they have been put together before then it is possible that your doe could have become pregnant.
If she is not eating and her stomach is swollen but you know she is not pregnant then chances are she is suffering from some sort of digestive issue. If you do not want to go to the vet for examination I found a site that recommended giving yoru bunny pineapple mixed with baby anti-gas medicine that contains "simethicone." Here is the link for more details: au.geocities.com