My life never feels finished and I constantly feel overwhelmed by everything. How do I organize?

I'm constantly overwhelmed by just... everything. The last few years in college has felt nothing but hectic, all the time, every day. It's been extra overwhelming this past few weeks because of two things that happened:

1: I just moved out the other day. I took almost all of my possessions with me and this made me realize how much stuff I have. I want to clear it out, but when I started going through it, I realized that I feel like I will need and use all of it eventually, and some of the stuff I don't feel comfortable about letting go because I spent my hard-earned money on it and I want some of that back (clothes that don't fit anymore, for example). I also have so many unfinished projects that I want to finish. So many half finished projects. My life enevr feels finished and it's beyond frustrating. Staring at it all sitting there, out, just made me feel so overwhelmed by how much there was.

2: The other day I did another little project. I plotted everything in my life out on paper, on a chart, kind of. All of my nagging thoughts and problems, all of the unfinished projects, all of my hobbies, all of the people in my life that I need to keep track of my relationships with. I thought this would help, but instead of making me feel better, it just made me feel so much more overwhelmed. I just have too much... too much. Too much stuff, too much going on, too many thoughts.

Lately my head has been feeling physically full (don't know how else to explain it), like it's about to explode. How do I organize my life so I don't feel this way?

tl;dr: I just did two things. One, I moved out. Two, I made a gigantic list of all the people in my life, all my nagging thoughts, all my hobbies, etc.. The moving out made me realize how much stuff I have (way too much) and instead of the list making me feel better now that it's all on paper and I won't forget any of it, I just feel more overwhelmed by how much is going on in my life. Advice?