Based on what you told us, it may not be sin. But please take time to reflect on why you became angry. I suspect since you posted here that there may be something about your reaction to this person that you are not happy with.
I learned a little trick to control my anger, and I was amazed at how it helped me. Remember the acronym START:
Stop - stop what you were about to say or do.
Think - think about the situation, and what you were about to do or say, and any possible repercussions.
Assess - how do you want this situation to resolve itself? What are your options? What would God want me to do? What do you think is the best action?
Reassess - How will this action play out. Is this God’s will?
Talk - proceed with your desired response keeping in mind what God would want you to to.
I hope this helps you as much as it has helped me. During this process, your anger is likely to have cooled off and your response will result in a better outcome. It really doesn’t take long to go through the process once you’ve stopped the emotional response that you may have regretted.
God Bless