I have this cat, Kittyboi. I'm afraid she's pregnant but honestly, I can't tell. She has gained a considerable amount of weight and is acting more friendly (ordinarily she is a pretty mean cat). Her nipples have become more prominant but I can't tell if they've turned any pinker (I don't remember what color they were before) When I gently press on her belly I can't feel anything.
So because of the last two things, I'm on the fence. Could the weight gain, nipple and attitude change, be a sign of her simply being in heat?
Also, she is being extremely caring of my newest kitten, Bub. Which is strange because ordinarily she hates Bub. Kittyboi has taken to sleeping with and obsessively grooming Bub.
Any ideas would be helpful (She, Kittyboi, has a doctor's appointment on the 24th, just so everyone knows. I don't want to take her in to get her first shots and risk hurting the kittens, if there are any)
Well the Vet will be able to tell you for sure if she is pregnant or not so it's best to just see then...until then though make sure she has good food to eat and keep an eye on her.
>^..^< 
