Seasonal depression?

I feel like I have seasonal affective disorder/seasonal depression/summer depression. Last summer I was in my worst bout of depression. I stopped eating and started to cut myself. I had to go to therapy for 6 months. School just ended and I already feel like I’m downward spiraling. I’ve broken down three times in the past two days.

I thought it could’ve been that I’m just sad about school ending but I was happy all week. But then I realized the same thing happened last year.

Why do I feel sad in the summer? Most people get seasonal affective disorder in the winter. Do you think I actually have seasonal depression?