How do I stop my imaginary life from influencing my real life?

Hi doctor,

I am a 19 year old girl. I have a very stupid habit that has caused a lot of problem for me, I have met a lot of psychologists, but I could never talk about my exact problem with them. It seems to be a ridiculous problem, but I ask your sincere help. When I was 15 years old, I watched a romantic movie which caused my problem, since then I made an imaginary life with an imaginary man in my mind. I have got involved with this problem for years. When I was a child, I had difficulties which I could not solve at that time, so I started fantasizing and tried not to involve myself in real life's problem. But then, there was no love in my imagination, I was a very happy successful girl, and I was a famous, respectful person. But after I got defeated at a state level game, I understood that I am not intelligent enough to achieve such goals, I was so depressed with no enthusiasm in studying. I got to know about sex and intercourse, I was confused and hated my gender, I thought of changing my gender. I had depression, and I was so disappointed about life. Then I started to imagine a man who lived with me, and I loved him so much. Instead of facing my life problems, I used to fantasize about him. From last year I have imaginary sex with him. The problem I have is that my life is interrupted by my imagination. I cannot deal with other students, especially boys. I have lost my confidence, do not have the enthusiasm to study. I cannot focus when I am in the class, and I do not take any efforts to solve my problem. I just keep imaging a peaceful life with no problems, sometimes when I cannot control my anxiety and stress, I start having sex in my mind. I do not know what to do, and I want to stop this imaginary life. How do I stop this imaginary life and love? I know this man is not real, and whenever my imaginary life becomes sad, it has an influence on my real life. I currently take tablet Levebel 500 mg, two tablets a day.