Is existentialism the one true way of life?

Before I knew about existentialism, before I knew the works of Nietzsche, Kafka and Sartre, I've been an existentialist (without knowing). It's hard to call one's self an existentialist, as I don't believe it is an -ism. If you are an existentialist as well, you know that it's not just a bunch of ideas, it's actually a physical feeling that completely changes the way you see everything. It started with me being extremely dull. I started to realize how meaningless television is, as it's just a bunch of people acting out real life situations, and we watch this for entertainment. That turned into more though. I began seeing things differently, and I don't mean a perspective, I mean I literally saw things and they looked different. For example, my hands. They were familiar, yes, but they took on a whole new look. I realized that I truly was a monkey by seeing my hands. I also started to realize how every human on earth is just an evolved primate, and we truly are alone in this world being the only species with our intellect. It made me think, we walk around on this tiny rock in an infinite nothing, killing each other for money, land, ethnic differences, etc. And it made me come to the conclusion: all our life is at this moment in time is a collection of everything in our past. I feel like I'm living in a movie that I'll never get to watch again, as I'm going to die someday, and I don't believe I will be living in heaven or hell, as I believe religion is something we've created as guidance and an answer to the unknown. Recently, I discovered what existentialism truly was, and decided to buy the Sartre book "Nausea". As I read the book, my heart dropped; everything that this man described, felt and went through is exactly how I felt (and still do feel). I was amazed, as I didn't even know anything about the philosophy beforehand. So, if I became an existentialist without even knowing any of its concepts, does that mean it's true? And what are your opinions on the philosophy? Also, sorry for my description of how I feel. It's not very accurate, but it's as accurate of a descriptions as I can get. Existentialism is extremely hard for me to explain, as for others as well.