Should I be creeped out by my teacher?

So, my math teacher is pretty strict and I've always been kind of scared of him. But then, the other day I had to ask him about a problem on the homework after school, so I went to his clroom and asked if I could ask him a question. He smiled at me, which was the first time I've ever seen him smile. Then he pushed a rolling chair towards me and told me to get comfortable. I sat down, and he stood up and stood right behind me, pretty close. I rolled the chair in farther under his desk to inch a little away from him, but then he just moved closer to me, and I could feel his breathing down my back. I showed him the problem I had a question on, anyway, and he leaned forward and showed me how to do the problem and what I was doing wrong, and in the middle of his explanation, his cell phone rang and he went over to answer it. He was laughing and everything on the phone, so I got up and I was about to leave because I was already kind of creeped out. Then he quickly hung up and told me that I shouldn't leave, that I should stay. Then I said that I had to be somewhere, and I just ran out. The next day, he was in his usual sour mood, again, but I couldn't get the image of him after school out of my head. Should I be creeped out by him?