I wasn't home, so my cousin sent me some photos. When I saw the photos I was shocked and excited at the same time. My cat( female) was mating with another cat ( male of course).There are one-two weeks since that.I think my cat's eyes change when she is hungry. From a dot, it goes like a sharp line.And I think she is eating a little bit more. But she isn't getting fatter or anything.
Of course the only way to know for sure is to take your kitty to the vet.
However, if your cousin saw the cats mating, there is a very high probability that she is pregnant. This is because the cat species has a remarkable built in survival mechanism. Unlike humans and many other animals, the female cat does not ovulate until stimulated by the male cat. This results in most matings becoming a pregnancy.
To directly answer your question, you will likely not see signs of her pregnancy until about 3 weeks after mating. Here are some signs to look for at that time:
Symptoms of being in heat have stopped
Her nipples may become pinker and swell
She may vomit (similar to human's morning sickness)
She may want more attention from you
Of course, abdominal enlargement (but you likely won't see this until about the fifth week)
Toward the end of her pregnancy, she will show nesting traits. She will try to find a quiet place to safely deliver her kittens.
Check out the following link to learn more: http://cats.about.com/od/reproduction/a/pregnant_signs.htm
It's important that you don't let her outside while she is pregnant. Otherwise, she will find a nesting area outside, and you may never find her again. Her motherly instinct kicks in, and the safety of her kittens is all she is thinking about.
If she is pregnant, may I suggest spaying her after giving birth, as soon as your vet says you can. Animal shelters are full of unwanted litters.
I hope this info helps, and I wish you and your kitty the best!