First, you have been thinking about this person recently. Maybe, you will deny it and say, "I didn't." However, maybe only you know it. In your heart, you have been thinking about this person for a long time. You fill the empty time you miss him with all kinds of things every day, but as long as you are free, you will still miss him. Therefore, when I rest and sleep at night, I will miss him and dream about him. When you wake up, you may not remember your dream when you were asleep, but you will still miss this person very much.
Second, you may have been single for too long and want to find someone to accompany you. Perhaps, you haven't been in love for many years. Recently, many people around you are in love, showing love in front of you every day, and you are abused. The more they show their love in front of you, the more lonely you feel. Therefore, you really want to find someone to accompany you, especially when you wake up and find yourself alone, you will miss someone very much.
Three, at least two hours before going to bed, you have been thinking about this person. You miss someone especially after waking up. The possible reason is that you have been thinking about this person before going to bed. You may think that this person will cry silently at the thought of insomnia. Even if you have slept all night, you still can't forget the memory of last night, so you will miss him very much.
Fourth, after you fell asleep, you dreamed of this person. Maybe you haven't seen this person for a long time, and after you fell asleep, you suddenly dreamed about this person, all kinds of past events with him, and the years we passed together. When you wake up from a dream, you may continue to recall the memories with this person. You will miss him very much and hope that he is still with you.