I also tend to do most of the things that you mentioned, to a degree - I tend to over think and over worry about the different possible negative scenarios of things that I am uncertain of how to handle or which I do not have any or little control of and I am heavily stuck in the past since my present life situation sucks (I don't want to get into it. I feel the same like Al Bundy from the TV sitcom "
Married with Children" as he used to say to his wife Peg or to his drinking buddies as he relives his past High School football glory days back when he was young, trying to forget his present miserable life "We are like the mighty dinosaurs. We have no future but we have a great past that we can revel in"). While I am concerned about inadvertently hurting or upsetting others, I guess that the first two previously mentioned items preoccupy my mind so much more that I do sometimes do the latter unconsciously but then I end up apologizing afterwards to the others whom I've affected for my misplaced thoughts and/or actions (Unfortunately, the last item is not something that is always in the front of my mind).
IMHO, I think you're wrong about yourself being a mistake - The fact that your parents tried to prevent your conception with birth control and yet you were born means that you were meant to come into existence (It was God or fate that dictated that you were supposed to be created)! I was bullied when I was a kid since I was short and not at all muscular (As an adult, I'm only 5'4" so, I'm not exactly basketball or football player material!) but I always stood my ground when confronted by bullies. If you don't outwardly show fear to bullies and stand up to them once in a rare while, they tend to respect you to a certain degree (In their eyes, you're still not a match for them but at least you would not be thought of by them as the "Weakest of the weak" aka Their favorite "punching bag"). Hmm... Even though it may be a bad thing, I would say that you didn't fail to become a bully in your own right (Or in you own wrong?).
I wish that I can help you with your game design and development skills but I don't know how to do any game programming either (I just know how to do client-server programing, writing business applications with a 4GL language like Visual FoxPro [Now obsolete] as the front end and a database like MS SQL Server as the back end). If you want to formally learn how to design and program games proficiently, I can recommend that you check out Full Sail (online) University ->
https://hello.fullsail.edu/brand_1ar_games (Be forewarned though, most of the hiring managers that I know in the business world would not hire people with degrees from an online university since many of those schools are thought to be "Fly by night" schools compared to traditional "Brick and mortar" schools that are accredited by the U.S. Department of Education. Most of those online schools are basically businesses that want to "sell" degrees. Most of them are not accredited by the U.S. Department of Education and rather are "Accredited" by private associations made up of their peers (Other online schools). However, I haven't come across any schools accredited by the U.S. Department of Education that teach game programming (They also teach music [To be used in games?] See ->
https://hello.fullsail.edu/brand_1ar_music_recording), so Full Sail may be the only professional education choice available unless you're one of those genius C++ programmers that can pick up a book on game programming, read and practice what is taught within those books and then code your own games from scratch (Or at least reuse a licensed game engine in your projects)!