@Regurge01 - Every student that gets into Harvard, Yale, Princeton, Stanford feels the same way. Or if they don’t, they are in for a rude awakening when they get on campus freshman year. Each of these schools has a near perfect retention rate for Freshmen. They very rarely make mistakes. When I got there in 1978 from my not so good public school, I was way out of my league. First semester was a killer. I persevered, hit my stride, went on to get a Masters degree and I am doing fine. My D, who went to a cushy private HS, had her moments during the first months (though not so much about schoolwork), but is doing fine now.
You did not take anyone’s spot. That spot is yours and you earned it or else you would not be there. There are not any charity cases there. Also, I am sure there are kids on the FB page that are just as nervous as you are. Be a trailblazer and be the first person to bring it up. You will be surprised how many others will respond they are feeling the same way.
Now - go forth and enjoy!! You are a part of a select few. Doesn’t mean you are “better” than those that did not get in, just that for whatever reason, the AdComs felt that you “fit” into the Class of 2019. No way to know why and so there’s no way to justify it to yourself or anyone else.
Welcome to the Ivy League (though you picked the wrong school)!!