I've had exes do some pretty messed up things to me. One of them went to a mental hospital and told the doctors that I told her to cut herself. The worst part about that? That's how she broke up with me. (I've been in the self-harm position. I would NEVER wish that or recommend that to ANYONE.)
I've blacked out and woke up in hospitals for seemingly no reason until someone told me I flipped shit after my girlfriend (at the time) broke up with me.
Anyways, the point is that there's always someone who is having similar issues. However, the problem with these feelings of depression is that it will always end up making you feel lower than dirt compared to someone else. It lies to you. It lies so much and in such a convincing manner that it makes a person end up believing that they are alone and that no one wants them around. Here's the most important part: THAT IS A LOAD OF SHIT Do not believe it's lies. Do not let it make you feel worthless, alone, dark, or whatever else. They are, again, lies that are easiest to believe in hard times.
Onto getting past it - I, again like you, am in my early-mid 20s living with my parents. It sucks and that alone is enough to make a person feel like a second-class citizen. It's part of the reason I play video games. They're fun, and I have an odd passion for it that no one seems to understand, but people in them have no idea who I am, where I come from, what I look like, etc. It's a quick and easy escape. I urge you to try it or something you have passion for when things feel too hard. Be careful, though, as it can very well turn into more of an addiction than a healthy, reasonable coping mechanism. Not a physical addiction, but a mental one. Similar to the mental aspect of the common drug and alcohol addictions, one can end up using it as an escape to a point where there is no other way to feel good.
If you truly feel like you have developed a mental illness of some sort such as depression, don't be afraid to seek help for it. Doctors, therapists, hotlines, friends, whatever. Don't be ashamed to ask. I always said the #1 cause of depression is no one to talk to. I realize more and more every day how truthful that really is. I'm talking about face-to-face conversation. Social networks, video games, texting, or phone calls will never replace our natural way of communicating.