17yr old in high school

Shit self-worth, esteem, image. There are times where I feel worthless, like complete trash, like a nobody with no purpose in life, and I’d sulk in my past mistakes and regrets. I can’t move on from the past. I would tell myself that I hate myself and that I’m unable to do anything, that I can’t really do anything. 

As overwhelming and confusing emotions build up, I could say everything just numbs itself out, where I can’t really feel anything, like a hollowness in my heart, just completely empty.

I would get frequent mood swings. One of the reasons for that would be because of irritability. I would get irritated pretty easily when I’m in an irrational state of mind, and that’s pretty much everyday. Just by feeling like I’m unproductive could play a big role in that. But I get mood swings especially when I’m provoked or triggered by any circumstance where I feel that I’m in disapproval (sometimes mistaken for plain disagreement to me). More into depth, I don’t like confrontation, negative connotations, judgment, and criticism. Anything that affects my already shit self-worth really. Could even be the littlest thing and I’d make a big deal out of it. I’d overreact, over-exaggerate, and make assumptions. I would act bitter as a result, or just plain out rude. But when I’m really at my breaking point, I would lash out. I would lash out on people one day and then the next act like nothing happened at all and everything is just back to normal. But I do regret it, I regret everything that I’ve done to hurt that person in any way, there are exceptions.
I’ve learned how to better control it now, but it used to be really difficult to contain, I’d scream, hurt myself, throw things around, and destroy things.
I’d isolate myself from the world and distract myself in any way to avoid those feelings, but that’s not so healthy.

It’s kind of like a fire, a fire in you that has been fueled, big enough to burn down everything in its perimeter. It has come to a point where it has overcome and overwhelmed you, taking control of you, burning and disintegrating everything with just so much anger and hatred.
And you’d hate yourself for it.

As a result, I’ve lost so many things for myself, great friendships, relationships, and I have lost myself in general. I’ve shattered people’s perceptions of me and my reputation. Lost my purpose, my sense of direction in life as well as my identity.

This is really just a vent, I am currently on the path for self-improvement as I am seeking help, but any advice from folks with similar experiences would be much appreciated.