My friend and I have been seeing each other a month now.?

We both agreed that our relationship would be one such as a homie lover friend ordeal. Today I forwarded him a tex that one of his friends sent me and he blew up. It was only a silly message that I found funny an he blew up.He wanted to know why he had my numb and why would he be sending me messages. I tried to explain it was no big deal but he said he didnt wanna talk and he has not returned my calls or text today. Can I get a mans perspective on this. Could he be jealous and starting to develop feelings. I really need to know what to do.