Me and my best friend were recently in an argument and we friends again. I have no reason to be sad but I sometimes just get sad for no reason. Can someone tell me what to do?

Ask yourself is the sadness triggered by your friend? If so, what things did they do or say that may have triggered the sadness? If it's something you can both talk about that's a good place to start. "When you said ___ it made me feel sad because of _____". Sometimes when you have a falling out with a friend even after resolving things it can take time to repair your trust, comfort and confidence in them. It can take time for your emotions to feel settled again, even if you were in the wrong or vice versa. No one can really tell you what to do, your know your friend and the situation the best and can make the best judgement.

Hello. There is always a reason for a feeling, but only you do not know that reason. You talk about the argument with your friend, maybe this sadness is due to that, do not you think? In all, sadness is a natural and human feeling, although unpleasant. This is not necessarily necessary, nor sometimes possible to understand, but your will is legitimate. In order to see more clearly and to better understand this sadness, perhaps a cat with a listener could help you in this voice. If you can afford it, a doctor or therapist could help you as well.