I dont know

Even if you don’t have the saddest life it doesn’t mean you can’t be sad.
If you resort to cutting there has to be a reason or something that makes you use that as a distraction from what you feel or as a way to convert mental pain into physical pain.

In order to figure out what you’re feeling, you have stop for a moment and think.
I would try and come up with better advices or ideas, but it’s a little hard without knowing more about you and your experiences.

Yet still, if you truely have no reason to do such a thing, you can try replacing it with other activities insted or other things that you like doing that can be a better distraction and a better result on your mood.

Hurting yourself physically is pretty risky and will only make you feel worse in the end.