Why do I get sick during the night?

Over the weekend, I went to Reno and experienced high altitude. I thought my ears hadn't popped yet when I got home, but it lasted for a few hours. My mom said it's an ear infection and she would take me to the doctor. I also had a sore throat and runny nose. I went to bed and woke up without an ear infection and sore throat, but still a runny nose. I took medicine for cold and cough, but around 7pm I felt the hearing in my ear go weak. This has been happening for 3 days and I'm curious as to why it happens at night.