Depression after avoiding someone

Hi, I am 18(M), studying 12th. I have been ignoring a girl with whom I was talking. She was more like my crush. I had confessed my feelings to her. She was flirting with me but suddenly she kept me in friendzone. I was like wth. Then I tried to move on but she used to msg me and ask me abt my day and all. The convo went and I thought this is how it starts, right? A female first ignores you and after some interactions or after knowing you completely she opens the door to her heart. So this went on for like abt 1 and half year until one day she called me her brother. I thought, she was just checking how I will react and I just ignored. We were kind of very close(I even know her period date not only hers but also of her mother. I know everything abt her from her birthday to her friends and all). When I asked her about her type in men then she gave a list and guess each and every point was kind of inspired from me. Her insta notes and all were all resembling to me(can't be a coincidence everytime). I look decent(at least better than her ex). But, still she friendzoned me. Its not abt friendzoning or "she didn't choose me" shits, but abt mentally draining me. I used to talk to her till late night. My study was gone and I became insecure abt my looks and all just because she ignored me. So, I started ignoring her. Initially, I stopped sending her reels and kept the convo minimal. But, after sometime I used to keep her msg on seen. She was kind of desperate and wanted to talk to me. She knows why I am ignoring her but still. I can't be her brother or anything. Also it hurts, when you are ignoring someone with whom you dreamed to live your entire life. I tried to block her but my heart didn't let me to. What shall I do next? Have I done anything wrong choosing my future over her? How to move on from her? How forget her? How to forget those dreams?(My english is kind of weak so sry for that)