Why is my cat so lovey-dovey?

So, we've been thinking about getting a dog, and it's almost like my cat knows it. I know it sounds weird, and your probably laughing thinking how strange this sounds, but he's been following me around. When I go to sleep and leave him in a different room, he wakes the whole family with long sad meows. Yesterday he was waiting for me to get out of the shower! I left for about 8 hours yesterday, and he was laying on the couch the whole time meowing, according to my grandma, who watched Niki (my cat) for us. Today he woke me up with the same drawn-out meows. He also won't let me sit down unless he is with me. Don't get me wrong, I love this way more than before, but he never did it before, why now? Is it because I spent so much time on the dog and not paying attention to him. No rude comments please. I would like to know