Do You Think My Cat Could Be Pregnant?

I rehomed my cat and I am now wondering if she may be pregnant?! She is an indoor cat and isn't one for trying to get out but about 3 weeks ago she went out and came back an hour later, I noticed small amount of clear bloodstreaked fluid from under her tail, after I wiped it nothing more came of it and my cat was still well and her usual self, after a few days I started too notice she was becoming very tired and hiding away upstairs in her bed away from everyone, now a few weeks have went passed and I feel her tummy is slightly bigger and shes still sleeping ALOT and spending more time on her own although still very affectionate when she is with me, her nipples seem to be sticking out more than usual but dont seem to have changed much in colour, I am looking for some advice while researching online, she has an appointment with her vets on Tuesday morning. Sorry for the photo upload she has been trying to get me to rub

Hi! Welcome!!
I'm glad you're taking her to the vet just to be sure
This article might help a little;
How To Tell If My Cat Is Pregnant?

Thank you, I have had a read at it thanks xx

let us know what they say

Hi, from your description, I do think it sounds like she could be pregnant, especially since she was outside recently, where she could have easily come into contact with intact males. Your vet will be able to confirm for you.

If an unspayed female has been outside unattended. . .she's almost certainly pregnant.

If you're not up for kittens, she can still be spayed, terminating the pregnancy. If you want kittens, ask the vet what to look for as she gets closer to giving birth to try to prevent any complications.