Should I cry?

Hello,

I'm almost 18 years old, and I'm never really feeling well mentally. I don't have any problems with my social life and actually have a lot of friends.

I often have very deep conversations with my closest friends, and I always lead the conversations. With my words, I often manage to make even very "masculine"-looking boys cry.
For some time now, I've been feeling incredible pressure and the feeling that I have to let it all out. It feels like everything is just too much for me.

But now to the point, I haven't cried for about 4 years and I haven't really talked about my feelings either. 4 years ago I broke up with my girlfriend at the time and that was the last time I cried a lot. But not since then. The breakup with my ex put a lot of psychological strain on me but that hasn't been an issue for 3 years and everything is actually fine in that respect. But since I don't know what to do anymore, I'm asking you. I'm feeling really bad. There are 3 days when I'm fine and I'm grateful for everything and happy. But for the next 7 days or so I feel like I'm sitting in the darkness. Just sad, angry at myself and listless. But then I also have this feeling of pressure. What should I do? Cry? I can't imagine that crying will achieve anything.