How long after being spayed does it take a rabbit to start pooping and weeing?

Hello I'll try make this a quick summary. Our female rabbit Zannah was spayed today and still hasn't passed any poop or wee. I got the call to say she was awake at 2pm (so I figure she was done a few hours before) and the vets said she had eaten a little bit but that if she's nervous she may not eat much anyway. I got her home after work by 5pm and she's been drinking and eating but still not passed anything. This takes it past the 12 hour point where I'm worried about GI stasis. I've rang the our of hours number twice for the vet (2 and a half hours ago and about 45 minutes ago) and they aren't concerned because aparently if she's got a GI stasis problem then she would have stopped eating. The vets did say they will see her if I'm desperately worried but that the stress from the car ride and going out may cause her to stop eating and thus cause the problem we are concerned about. Some research online says it can take 24 hours to pass after being spayed so I wanted some advice on if people think I should take her in tonight? I'd be down in a flash if it didn't carry the potential of making her worse but I'm really worried ill leave her and she will be sick or dead tomorrow. Ive told my partner (he is working nights so isn't here) I am going to nap for an hour and re evaluate. Thanks in advance. I'm hoping I'm just being overly worried.