I have just started a thesis-based masters degree. 

My supervisor has asked me to help with another student's project. So I am working with another student of my supervisor. We work together and send him a report weekly. We send reports on time.

One time our report had a mistake, the professor got mad at me (at that time I sent the report to him). He told me unpleasant things and I got really disappointed at that moment and it happened two times. It was weird because firstly he was very good with me and this behaviour was very unlikely. Secondly, he was not mad at my colleague (another student) we were working together.

Both of us wrote and sent that report and both of us made that mistake. Why he was not mad at him? did he tell any bad thing about me to the supervisor?
What should I tell to my professor? I feel very bad. He made me feel that I am useless.

I heard that my colleague has a bad reputation of gossiping about others to the supervisor.

I should add that my colleague, thinks that he is the boss in the lab and he sometimes bullies me and tries to correct me in everything even when we are filling a form which is not related to the project.

How can I handle this situation?