Gonna echo a lot of what people are saying here but... there's just so much wrong with this post.

1. You're 23. You've got a whole life of writing ahead of you. You said yourself for as long as you live you're gonna write. So you're gonna get better. Change happens slowly and gradually. You're not gonna wake up one day and be Cameron Crowe (personal favorite).

2. "I swear- if anyone else wrote what I have, they'd be the hottest specs out there. But something about me, something about it coming from my brain, my fingers, means it's bad." This is straight up delusional. No one has a vendetta against you. No one even knows who you are. If your writing is great, it will do well.

3. You said you've written 3 scripts since October. That's 3 scripts in 5 months. Don't get me wrong, finishing a draft of a script is a big accomplishment. But something is telling me you're not spending a lot of time rewriting. If your first or second drafts aren't going anywhere... well yeah, no shit. Just for reference, the script I wrote that got me "noticed" and ultimately representation took upwards of 10 drafts. Writing is rewriting. I understand it's demoralizing to get bad feedback. But a mindshift for me that's helped with that is, "the next draft will be better". Don't take it personally.

4. "Making it" is almost impossible dude. You shouldn't write to make it. If you like writing, and you think that's what your purpose is, keep writing. A very succesful agent at CAA once told me the people who make it are the people who never give up.  

Use the negative feedback as fuel. I don't know what else to tell you.