Why do I miss her so much??

I took chemistry over the summer and it was the hardest and most stressful summer of my life, I never thought I could pass but I actually passed and got a good grade because of this teacher and I can get apply to veterinary nursing school which is like my dream job in a couple weeks, Yesterday was the last day of class and I gave her a card but I feel so sad. I want to go back and visit her but I don’t know if that’d be weird or not. I really feel like I shouldn’t because it’s just a college class but I really wish she could stay in my life and go to my wedding. I don’t think I am normal because I realize that’s never going to happen even though she was my favorite.