Lethargy and lack of appetite

Real early yesterday morning my cat rajah threw up and it was just watery. I hadn't fed her the night before cuz wed be traveling to my parents the next day and she gets carsick.

Well she didn't eat yesterday or today. And she's really lethargic which is scary cuz she's usually so playful. Checking her liter box shows urinating but no poo.

She's my first pet and I love her so I'm worried. She turns one in november.

I think she needs to see a vet urgently. Cats can get really sick if they don't eat - their bodies can't handle it. 

I'm going to take her tomorrow. I'm just really worried.

Its really important to try to get her to eat something tonight. Try 'human' food like plain cooked meat, or even tuna fish, if she won't eat her food. It almost doesn't matter what she eats at this stage - just try to get something into her, and keep a close eye on her. 

Did she ever eat anything?  I suppose the travel could have upset her.  Not eating the night before travel could have caused the watery throw up, as cats' stomachs will produce acid in anticipation of the meal they expect is coming.  If it doesn't come, then they have excess acid that sometimes will cause them to throw up a sort of saliva-ish vomit.

Then after that if she went in the car and to a strange (to her) place, her entire world has been turned upside down.  And being lethargic goes right along with not eating...no fuel, no energy. 

As Columbine said, if cats don't eat, then it can become a very serious issue, as their livers can shut down.  They are complicated creatures   If she still hasn't eaten anything, you definitely need to get her in to see a Vet to see what's going on, especially since you aren't seeing any bowel movements.  Constipation can also result on not eating, and you want to make sure she isn't impacted or have a blockage.