Knee on Knee injury?

yesterday, ( about 17 hours ago) I collided with another player's knee in volleyball with my knee. I immediately went down and couldn't get up for about 30 seconds. When I first got up, I could not put any weight on my right leg and I hobbled out of bounds. After taking about 5 minutes off, I decided to walk it off. It was working. But on the car ride from the beach to my home, I had pain in my knee which was because I wasn't walking. Anyway, I walked at home, got better, then went to bed, and when I woke up I could not move my knee. My knee is better from this morning but worse then yesterday. Whats wrong? Is it just a bruise that will go away or is there structural damage? My knee cap is not swelling, and when I put physical pressure on it(not walking) It doesn't hurt. I'm icing it. Whats wrong and what can I do to make it better?