I'm so confused

This is a secret that I've been holding in for a long time. Something only me and my best friend know. Towards the middle of my senior year (about a year ago), I got really strong feelings for one of my teachers. I was 19 and she couldn't have been much older than 30. First, you should know that I'm the type of person who doesn't believe anyone could like me. If someone shows interest in me, I generally just shrug it off saying it was my imagination. For the longest time I had myself convinced that I wasn't acting on my feelings because I believed she would never feel the same way, and maybe she didn't, but I swear there were sometimes she gave me... a different kind of attention than the other students. I would catch her staring at me sometimes when she thought I wasn't looking, and sometimes if she realized that I caught her, she would give me a little smile until I looked away. Still, I was convincing myself that it wasn't there. My best friend however would keep telling me that I should "see the way she looks at you when you really don't see her" my best friend would also say that she treated me nicer and treated me different. My best friend was very convinced that she had some feelings for me. So more towards the end of senior year, those feelings I had got stronger and stronger even though I tried really hard to deny them, knowing it wasn't okay for me or her to be together. But I couldn't help but to try to get her attention more. This is when things started going downhill. I would get nervous, so I said silly things, and got very clumsy around her. But it only got worse. A few weeks before school ended, I felt comfortable enough with her to tell her about my ex(who was another one of her students) and how she broke my heart. This was not at school, but on a school trip that she took me and a small group on. She didn't say anything, but she listened. Then the next fall, I started dating a girl not much younger than me, but she was still in high school (I'm in college now), in my teacher crush's class. She knew I had a crush on her. And the last few times I've seen my teacher crush, she seems.. extremely uncomfortable around me. And I swear she avoids me when she can. Which is really confusing. My best friend is still convinced that she has feelings, and I just don't know. I don't know if I should believe it was there to begin with.Anyway, I know teacher relationships are usually frowned upon. I know a lot of you will say it is morally wrong. This is stuff I know. And I wasn't planning on pursuing any further. I just want an idea of what may have happened.. why this happened so randomly and abruptly. Especially AFTER I left high school.

She isn't married, and she never talked, had pictures, or hinted at a significant other. I never asked her because at the time she was my teacher so it didn't feel appropriate to ask.

It is possible that your best friend edged you on and the teacher might not have had a hint. She might have just looked upon and after you as a student. Student-Teacher relationship is special coz the teacher looks after the student as one who is to be mentored. Among a whole class each teacher will have some favourite students (due to IQ, behaviour etc.). So her looking at you could have been just that. And it is possible now she has a hint that could be the reason of her discomfort. It is also common that the teacher becomes your first crush. But best to leave it at that coz the age difference will coz issues later on.