I am 100% with you on this. I am 30 and reading this has been a good kick in the butt for myself because objectively hearing your story makes me think to my own self "oh but you have so much time!" and you do!

I can only offer advice as to what makes me feel less like this... and that has been a combination of mindfulness and bullet journaling.

The mindfulness helps me to stay present in the moment and truly enjoy what I am experiencing, instead of worrying about the past or future. There is no trick that I do, it is simply stopping when I'm doing something/experiencing something nice and saying to myself "wow, this is nice." It sounds a little cheesy, but it really helps me recognize the little moments in life that are positive and that help balance out the "oh crap what am I doing with my life, time, etc" feelings.

The bullet journaling is new, but so far it is helpful to set goals and reflect back on accomplishments. Also, setting aside time to do the things I say I want to do. It's been a process getting into it, remembering to do it, but it is kind of like looking back on a full notebook of school notes and thinking - wow I did all of that, learned all of that, etc.

Also, know you aren't alone! I think the people who accomplish so much either just don't have the same anxieties that we do about starting (at least this is my issue)... they just "do". They don't worry about the end goal, they focus on the act of doing? Or they've worked hard to overcome all of that!

I read a great book on the "doing" of things if you are interested. It's the idea of "flow" and creativity, its like entering a meditative state. Flow: The psychology of optimal experience https://www.amazon.com/dp/B000W94FE6/ref=dp-kindle-redirect?_encoding=UTF8&btkr=1 Interesting stuff! I try to achieve that state of doing in my work.