Help me! My kitten is 2 months and he was neutered 3 days ago? His pee is brown?

Please help! My kitten is two months, male, neutered three days ago (we adopted him after the third day), and now he has been peeing almost frequently the past three days. His brown pee is the size of a quarter. He meows a lot and he purrs unexpectedly at times. He has been sneezing in my house for two days. It's his third day with my family. It's our first time raising a kitten and i'm afraid something really bad might happen to him. I'm paranoid at the moment because this worries me too much. We've been playing with him too much and i think that's what caused it's urination. Please help. About 10 minutes ago he was running like crazy like the world is about to end. Now he's sleeping on top of his carrier. I don't want to see an animal die in front of me and i've been bugging my sister to take him to a vet. Help please!!!!!