When a girl says goodnight first, it could mean one of two things.
If her reason is the first one, you need to say goodnight with love and let her rest. However, if it’s the second reason, you need to ask her why she’s upset. Talk to her about it and make sure she understands your point completely. I always suggest couples to be as vocal as they possibly can about their feelings. Talking, respectfully, will always end up fixing things and clearing all of the misunderstandings. We are all human, we make mistakes, and we misjudge, but talking will always fix things.
If she is mad at you, you need to ask her why. You need to get to the bottom of it and fix things. Why would you sleep in an angry mood when you can fix things and sleep peacefully? It’s always better to fix things and sleep peacefully, with a happy heart. Talk about things and fix them, never sleep angry. Don’t bring that same energy to the next day, start fresh and start satisfied.
If your boyfriend wishes you with “sweet dreams,” it means he is genuinely in love with you, and he wants you to have a peaceful and relaxing night’s sleep. I always pay attention to the small gestures in relationships; it’s still those little things that matter more than grand gestures of romance and love. When your partner says “sweet dreams” to you, it means they know how hard your day has been, and they want you to forget about the hardships and relax; it’s a beautiful thought and a lovely gesture. I would appreciate it and love it.