why does literally everything somehow ends up making me anxious and then depressed?

I have been in this situation before when I felt I cannot do anything successfully and I considered myself as a failure because of my anxiety and depression towards things come up in my life. I used expressive-writing paradigm to helped myself overcome this negative-thinking loop through observing and analyzing my feelings, emotions, and experiences rationally. I think keeping this journal really helped me understand my thoughts and myself. And it brought me to the tipping point of my life that I could recognize my own capability, and acknowledge that I can do things great instead of being tripped in anxious worries. Wish my personal experience helps!