Cat not keeping down food

Hello, I just found and joined this website because of my worrying about my baby Laila. She is 5 & 1/2 months old and just had her spay surgery almost 2 weeks ago. This morning I noticed a few spots of vomit in the bathroom, at first I wasn't totally sure what it was because of the color and texture. It was a pinkish-orange color and a bit powdery, maybe just because it was dry if she vomitted early on in the night? Her food is dry food which is also reddish in color, so I'm not sure if it's just her food giving the vomit this color, or if it's blood? I fed her a bit less than I usually do before leaving (also watching to make sure she ate slow), and when I got back home ~7 hours later, I found another spot of throw-up. Her behavior is normal, she's still playful and happy to give excessive amounts of love-bites as usual. However, another note, since her surgery I have noticed a decrease in her appetite. I had assumed it wasn't a big deal and that it had to do with her surgery, and that she would get over it quick.

Should I get her to the vet ASAP?

Any advice or anything I need to know?

What brand of food do you feed her? It's probably the dye; not blood. It could just be that the food doesn't agree with her. And heavily dyed foods usually don't.  I think a vet check wouldn't hurt.. if her food intake isn't much you should get her to the vet. Not eating can cause health issues.

Is she still vomiting?  Kittens sometimes get into things they shouldn't, which can cause a bout of vomiting, but if it continues for any length of time (say 24 hours) I would take her in.  Particularly if her appetite is still decrease two weeks after surgery.  Yes, one would expect it to be decreased immediately after surgery, or even for a day or two as she recovers, but not for this long.