What should I do when my best friend stopped texting me back?

I am gay and my best friend is a straight man. We went to the same university, but we really became close after we graduated. We worked in the offices and felt alone, especially our circle of friends was smaller. So, we started texting each other a lot and nearly everyday for four years, and it used to be very fun. We have the same personality and share similar worldviews, so he feels at cease to confide and talk to me about almost everything, like daily happening, office gossips, his shopping list, his hope and fear, his future plan, his family and girlfriend. Moreover, I have been his roommate for one year and that made us closer. When I feel so close to him, I usually express what I think or feel without thinking.

Several weeks ago, he had an appointment to hang out with other friends. At first, they invited me, but change the date. When I knew, I called my best friend to ask him where they were and if I should go to meet them at the moment, but I was cut off for five times. I got very angry and texted him to ask if he still considered me as his friend. But when I calmed down, I send a message to apologize him. Next morning, he replied my message with a neutral emoji and didn