Depression? I guess idk

Why is it so hard for teens to explain their emotions? I’m sad but when someone asks why I can’t explain it. There’s so much happening in my head. Can anyone offer up some advice?

I’m seventeen, just trying to fit in at a nepotistic school/small town. I have no friends, no siblings (none that live at home (two brothers, too busy and difficult to talk to)) and my only companion is my boyfriend. We’re great friends and all but I can’t tell him everything. And I’ve gone through almost all of high school without the typical best friend that everyone else has. I don’t know what it’s like to have a second home or someone that knows every detail of my mind. I haven’t been to a slumber party since I was 6 (back before people knew what popularity was).

I’m a straight a student, almost top 10%. My gpa is somewhere around a 4.5. All of the honors classes I take, I have the same 15-20 classmates. Every single one are popular in some way whether it’s money, or their last name, but because I have neither (we have money but not old money), I am not close with these kids, but my values don’t line up with the kids in the normal classes. So I’m stuck with nowhere to sit at lunch, and I’m forced to sit in the back of the classroom because certain friend groups like to sit together and I don’t want to be in anyone’s way.

When school is out, I go home and scroll Instagram and watch other peoples lives play out as mine just sits and rots away. It’s Christmas break. I have no plans, no close friends, and my boyfriend went full time at his job since he’s out of college for a few weeks. My parents work long hours. So here I sit in my pajamas for 20 something days. Perhaps it’s cabin fever.

What do I do? I feel lifeless