HP hit it on the nail but I wanted to add some points as I've also gone through my phases of darkness @Mark Karhan These moments are very natural, and actually a good sign, they probably show you that you know something is not right in your life, and that can lead to major changes for the better. I'm not sure if this is the same you are experiencing, but look up "dark night of the soul", it's something that most people go through at some point (or multiple) points in their lives and can be very transformative.
As someone who's been there before and changed for much better, I can tell you that if you can get the basics right (the things that HP mentioned), you will feel much better overtime (it won't happen overnight). Make an effort to keep a routine and do the basics for a while. Diet is a very specific thing, and I'd recommend to get informed on all the available information now, but in general you want to avoid (or reduce) all the processed shit, and favor whole foods (whole grains, vegetables, legumes, meats, eggs, etc...). You also have to work out (or have some regular exercise) if you don't already. Walking around the block is good, but preferably you want to do something that will exert your body and challenge you. That will release testosterone in your system, and get you rise up and work for the things you love. Working out is great if you can find a cool gym nearby, it will also help you to socialize.
Doing those things for a while will improve your sleep immensely. And when we eat, sleep and exercise well, everything else gets much much easier.
If you are feeling in the dumps mentally, avoid social media like the devil. It's a tool for hypernormalization, where any opinions or looks that are not accepted by the current ideology, will be ostracized, ridiculed, or downright attacked. You don't want to be exposed to that when you are still forming your personality. Be yourself, that's much more important than falling in line just to be accepted. Social media has also been linked to severe depression and radicalization (ever seen a friend join Twitter and all of a sudden he's an angry activist?). Stay away from pr0n too, that will completely wreck your dopamine receptors.
The kinds of thoughts you have also have a huge impact on the kind of experience/existence you lead. As an example, if you believe you are fucked up, you will behave in a way that will make that a reality. If however, you twist that belief into "I'm going through a hard moment now and I will get out of it stronger on the other side, no matter what", that's much more productive and will lead you to better results. Write that on the wall to remind you several times a day if you need to. Meditation helps a ton to keep the mind clear.
@Mark Karhan You are a great guy, very smart and you have a sharp mind. Use this opportunity to find yourself, and become someone you will love Know that you are not alone and let us know here how you feel!