I always think of someone in my heart. What happened? In fact, the more you miss someone, the more she will appear in your mind all the time, and sometimes even dream about each other. Most of the reasons for this are that you have a good impression on this person. To put it bluntly, you just like each other and secretly love each other. Because you haven't got it yet, you will constantly want to get the other person's approval, so you will always miss her.
There is another situation, that is to say, your life is not particularly full, and you always have leisure time to be in a daze, so you always think about it when you are not busy, which gives you time to miss each other. So, if you don't want to be like this all the time, you should enrich your life and keep yourself busy, so you won't have time to think.
Thank you. I hope I can help you. Come on!