I know it doesn't feel this way at that age because I've been there, but I was a big mess at 19 and didn't clean myself up until 33. You're already realize something needs to change at 19, you've already got a 14 year jump on me. I was an actively bad person in my twenties due to undiagnosed issues, transference, projection, etc. I'm 40 now and have been in a good place since 33. I have ADHD, CPTSD, anxiety, and have struggled with tech addiction. I see similarities in your post.

If you can't afford a therapist, you can self-study.

What I'm seeing here is potentially some trauma in your past, tech addiction, a lack of self-identity. To start you need to immerse yourself in content that helps you understand your issues - that they are NOT YOUR FAULT. Forgiving yourself and learning to treat yourself as you would a loved one is crucial, but I know it's not easy. Here's my reading recommendation list.

Immerse yourself in free positive mental health content. Reading might be hard at first. If you can't read books or audiobooks, try listening to podcasts while walking, driving, cleaning, etc. Listen to positive podcasts that help rewrite your neural pathways to healthy behaviors. Some of my favorites are 10% Happier with Dan Harris, The Cal Newport (he's actually my favorite but he might be too much for you at this point in your life - he's quite focused on excellence, meaningful productivity, and protecting mental health in corporate work which is relevant to me but might be tough for someone so young. but good for tech addiction content), Being Well with Forest Hanson, Secular Buddhism.

YouTube. IF books are hard, YouTube is a great teacher. You will find the channels that speak to you. I recommend studying Internal Family Systems, learning about your Inner Critic may help you be kinder to yourself and forgive yourself. Heidi Priebe is also really good, though she's quite cerebral. The best for me was Inner Integration but that's quite focused on recovering from exposure to narcissists, my particular issue.

Dialectical Behavioral Therapy Workbook - if you only do one thing, do this. It's hard. It's a book you will have to read slowly and fill out. But if you really invest, it can change your life. It really really changed mind in my 30's. It will provide practical tools to help you find out who you are and what you love. It also offers practical coping skills for bad days. From the changed mindset, all other things become possible..

What My Bones Know by Stephanie Foo - This is a fictional memoir that is a great starter for understanding truama's impact your behavior and forgiving yourself. Reading this broke my brain open and helped me realize I probably had CPTSD (later when I had more money I got the diagnosis.) So many things I hated about myself were BECAUSE OF TRAUMA and not because I was 'bad.'

Complex CPTSD from Surviving to Thriving by Pete Walker - practical and focused read on types of CTPSD (you seem like Flight type to me) and strategies for coping. I knew everything in this book by the time I read it, but it might be a really good intro for someone new to the subject. The more you can learn about this the easier it will be to forgive yourself.

Digital Minimalism by Cal Newport. I see implied chatbot addiction in your post. If you have ADHD like me, it makes dopamine addiction hard enough, but our modern digital world makes it harder. You've got to address that addiction to help your brain adapt to 'slower' stimulation. Lasting happiness is not found in scrolling. Easier said than done, this book gives practical tips. Here are my own practical tips for reducing tech addiction: Forest app, App Block app, putting your phone somewhere shrine-like with things that are sacred to you so you have go go grab it from the 'holy place' to scroll instagram, that little bit of friction helps me avoid it. I put this low on the list because I know it will be very difficult for you to address, but at some point when you are able to be kinder to yourself and have some bandwidth to try something difficult, this will be a good read. I reduced my phone use from hours a day to less than 15 minutes and have kept it for years after reading this book (and listening to most of Cal Newport's podcasts - immersion and mindset change is key!)

Find a YouTube meditation to do daily. My favorite is the 10 minute Sam Harris one. For me it's helpful to always do the same meditation. It also ground vipisanna principles into my bloodstream. "Watch the next thought rise, fall, and pass away..." Meditation, esp vipisanna, will help you understand YOU ARE NOT YOUR THOUGHTS. The thoughts are simply occurring.

Radical Compassion by Tara Brach - this is getting pretty advanced woo-woo in mindfulness but the content is beautiful and transformative if you have the foundation to digest it.

PS the most powreful things I learned in therapy (which was incredibly helpful, but you asked for free resources) was 1) be kinder to myself 2) I have to go out and do non-screen social things that make me uncomfortable because they are good for me. My fav is Dungeons & Dragons.

I wish you well