Why does my cat "hate" me now?

The most common reason your cat is not so loving right now is because he suspects you of abandoning him in a way. Animals, even though it may not seem like it, have very complicated feelings. He doesn't like that you brought new kittens into the house and thinks you are cheating on him. I know that's a silly answer but it's true. The best option right now is to coax him into a room with a door, enter with him, and close the door. T he n just hang out in the room a couple hours. He will eventually come up to you and start loving you the same.

Animals can get jealous too, every time i give some attention to our cat the dog always comes over if he's in the room expecting the same! Generally speaking cats don't get on well together unless they were raised together, they're instinctively suspicious even of each other

She will get over it, in time. Even kittens are HIGHLY TERRITORIAL and the other two kittens invaded your kitten's space. Even worse, you spent time with the intruders. Give her a few days to a week and all should be well again.

It's the scent. Wash the clothing you wore and soak in a hot bath and scrub your hand with a brush paying attention to the fingernails.

No it just doesn't know what you where doing with the other kittens. It will return to normal once it sees the others are gone.