Why Is He Acting Like This?? He's Really Acting Weird To Me...

I'm 16 and I have this teacher & he (my teacher-crush) is just 20. So, its my 1st time to have a crush on a teacher. (if you happen to read my previous story)
I developed a crush on him and I liked him even more when I learned a lot of stuffs about him (more about his life, hobbies, studies, family & friends - seriously A LOT more than any student/teacher had known but I'm aware that there's a lot more to know)

The thing is, whenever I try to recite, he never called me. He'll say "Other hands please" (he means that others should also participate and recite) He still haven't called me & I'm raising my hand and he still got the nerve to ask for 'other students'. What the hell does he think about my hand? A foot? A head? Darn. Kidding aside, I meant..he acts as if I'm invisible though i'm obviously not. That happens ALWAYS. I sort of felt awkward to him. These are also the things that happened:

>> short eye contacts & just pass by each other whenever we meet in corridors w/o saying Hi or anything.
>>> He is always sweet or soft with everybody & also smiles at them & act friendly but NOT to me
>> I tried to ask permission to go to the CR and he said "NO!" firmly then he started saying things I couldn't understand. Bottom line is, NO.
>> my new seatmate called him in class & asked something. He instructed my teacher to come closer but he was so firm at declining. (My new seatmate even questioned him why he was fine to come closer to them before but now he doesn't want to - he just keeps saying No) That made me think that he doesn't want to come closer because of me.
>> During recess, he used to look at me a lot - quite frowning
>> in class, he refuses/tries hard not to look at me. There are times he look but he quickly looks away
CONCLUSION: With all these, I started to feel that he hates me.

There was a time when I messaged him in Facebook (just about school stuffs). One day, I met him upon going to the CR. From afar, we both saw each other. As I came closer, he TURNED HIS BACK ON ME. When I was near him, I called him & asked him when will we have a meeting (he also became my moderator in one of my electives) then he started talking & was stuttering & was saying the same things over & over as if he was rattled or nervous, idk. Then I just said "Oh, ok sir" then just when I was about to go, he said, "Wait! We should have met a long time ago." (OF COURSE, pertaining to our meetings in my elective class) then he smiled at me. It was the 1st time he smiled at me! There were also times when we start having some short talks (in the presence of my friends).

Then things starts to change lately (idk why)...
>> Elective Class: we're only 5 that time including him. A lower level co-member asked him if his subject is hard then he smiled then he called me & asked me if its hard and I said "YES! So hard blah blah" lol. We also had some small chats again.
>> In the lab, he suddenly called my name and said "Be careful" & "Take Care" But I swear, there was no danger at all. He just like..randomly said that & it was kinda weird but yeah, I was happy :)
>> I was talking to my classmate about a book then he asked what we were talking then I answed him. We started talking about it and he was smiling and looking kinda comfortable the whole time.
>> ONE OF THE MOST NOTICABLE THING IS: my new seatmate for the new quarter called him once. I asked him a queston & SURPRISINGLY, He came closer even though our place is kinda messy & there were bags scattered around. He made his way closer - Very close to me. We didn't even ask him to come closer. O___O
>> During discussions he was looking at me. Some short looks, others quite long.
>> He was friendly to me during class discussions
>> ANOTHER SURPRISING THING, once in class, he was discussing and I said something about the lesson (not really loud) but then he called out my name-I was surprised (He was paying attention at me!) & asked me to tell it to the class. After that, he said "Very good" and smiled.
>> Every break, I caught him looking at me a lot of times. (that wasn't new to me)
>> One time in the canteen, he was sitting alone then he saw me. He really looked at me wherever I go & when I finally sat down in a table in front of him (which was a few table from where he is), he suddenly looked rattled, put his plates in the dish then ran away. Well, I find that really weird.

The way he acts now, ALL THESE WAS NOT LIKE HIM AT ALL. (when it comes to me)
Those things happened lately and he was now smiling at me unlike before that he just frowned and was harsh (but he wasn't like that to others - making me think that he hates me) He also seemed more attentive & comfortable though sometimes quite nervous to me.

Additional Details
So...I was really happy with these changes.

Something goes weird again...
Yesterday, I went straight to him in the faculty after our class retreat wearing a blue top bcoz it's his favorite color. I just asked him if we have a meeting for the elective class. He said no then I quickly went out. A few moments later, he went out of the faculty and headed towards my direction (I was now with my friends that time) They said Hi to him so I also said Hi. We talked to him and he looked at all my friends but NOT TO ME. He only looked at me ONCE and it was a very SHORT LOOK more like a glance. Then after talking to us, he went back to the faculty at once. That was weird. Plus, he seems quite cold to me too.
I thought we were kinda okay already?