Is this anxiety, depression, or both?

Is this anxiety, depression, or both?

Sometimes I get stressed out a lot. Usually, I feel sick to my stomach, but nothing else happens. One time out of ten I'll shake a little and I might get dizzy for a few seconds. I haven't had problems with breathing, so I don't think it could be panic attacks. I don't even know if it's anxiety. I also used to cry a lot, but I can't do it now. It's not that I feel better, I just can't get the tears out. My friends are so happy and I feel alone. I've been suspecting depression for a little while now, but I can't imagine how to tell my parents. I'm their only child.

Anyway, any advice will help