Is it depression?

I recently have been very emotionless and I’ve lost interest in many activities. I also self harmed for the first time ever just so I could feel in control of my emotions for once. Some days I’m overly happy but most days I just want to sleep and I feel nothing or I just feel everything at once and over think every life decision. I don’t know if it is depression because I don’t want to self diagnose but I also don’t want to tell anyone about it to get help.