Should i talk to my ex girlfriend?

Hi. This is a long post and I appreciate anyone who bothers to read it and vote/comment. This is important to me and I am very thankful for any advice. :)

I don't know if this is love or obsession, but I can't stop thinking about my first girlfriend (we can call her "C") after over a year of being broken up and a few months after not talking with her. We were together for almost a year.

In January 2014, she and I had a petty argument and in my frustration, I walked away from her and we didn't talk for a month. I thought she was over me, so I decided I should try to move on.

February-March 2014, I tried to get over C by finding a "rebound" girl (let's call her "M"). M was C's long-time friend, which ultimately made C very jealous. M developed feelings for me as well, but when I admitted to manipulating her, M stopped talking with me. C begins talking to me again and revealed to me her jealousy. I arrogantly and sadistically taunted her about how I successfully manipulated her into admitting she had feelings for me.

April-May 2014, C tries to become friends with me again. I never fully apologize for my actions in March and I am still not over her. I talk to her in a condescending tone to hide my feelings. Eventually, she stops talking to me because I point out that she had some period blood on the back of her shirt (which is pretty gross, to be honest).

June-September, C and I don't talk at all. I am now very convinced C is over me, but I am still not over her, because I'm a clingy sack of loneliness.

October 2014, she and I tried to reestablish a friendship, and I tried to make it work by talking to her and texting her whenever I feel the time is right, without revealing I still have feelings for her. I fully apologized for my actions in March. I eventually found out via a mutual friend that C liked another boy, let's call him "K". I was okay with this, and what I wanted most from C was not necessarily a romantic relationship, but a genuine friendship. This time I no longer spoke in a condescending tone, but she seemed colder towards me and I felt as if she saw/treated me as a different person than she did back in January (which I was).

November 2014, my objective rationale told me that C and I had no chance together (as partners or friends) and I ultimately decided to stop talking with C so I could get over her.

I explain to C why I was distancing myself from her:
-I felt she and I were incompatible as partners or friends
-I felt our history changed us into an incompatible pair
-I felt like she saw me as a different person and treated me differently than when we were close
-I saw her as a different person
-I didn't feel like I deserved her, considering how much I treated her like dirt

In our final conversation, she revealed to me that:
-She is over me
-It took her several months to get over me (she got over me during the summer)
-That had she not met me, she would have felt like her life was "incomplete"
-That she feels there is a reason why, after every time we stop talking to each other, we begin talking again (but doesn't go into further detail)
-From January to May, she felt her feelings for me were unreciprocated because I treated her in an indifferent fashion. The irony of this statement.
-She wanted to be friends with me

After formally saying goodbye, it was our first peaceful way of ending communication. When I would pass by her in the halls (we go to the same school), it was really obvious that she deliberately trying to avoid eye contact. Sometimes, when I pass by her, I would see her try to initiate conversation with my friends in front of me, probably with the intention of making me jealous or awkward.

November-Present, I learn from a mutual friend that C no longer has feelings for K. During this stage, I entered a stage where my grades fell because I was thinking about her even more. I was reevaluating our relationship and what I wanted to do about her. With her absence my feelings for her have grown stronger. By being unable to look at her face during conversation, I have come to appreciate her visual beauty and grace more from a distance. By being unable to talk to her, I fantasize about hearing her voice again. I fantasize about holding her small, warm hands again and embracing her and staring into her eyes. She is *literally* the Girl of my Dreams. I love her more than when I was in a relationship with her.

When I do see her, she seems lonely from a distance, like something is missing, and I wonder if I am that missing part. She seems more solitary than usual and any interaction she has within 20 feet of me seems unnatural. She hasn't had another boyfriend since our break up, at least I don't believe she has.

What should I do about C?? Even 14 months after our break up, being able to find a rebound girl and 11 months of not talking, I haven't been able to get over her. I feel like these months of silence have given me time to reflect my actions and I feel like I have matured since then. She still doesn't know I have feelings for her. What should I do about her?