I can absolutely relate to this. Last year, I matched to my #4, and while my top five sites were lumped relatively close together in terms of what I was looking for in an internship, I still had that feeling of "but my #2 has X, and #4 does not." I felt like a jerk for thinking like this because some people did not match. Or other people matched really low on their list (#12 for example), to places they had pretty much forgotten were even on their list because they thought there was no way they would end up there. So I kept these feelings to myself for the most part (my husband the exception).
The whole parade of people at your school saying, "I matched to my #1 YAY" really jumped out at me, because I felt the same way last year! And worse, some of these people who matched to their #1 or even their #2, they knew I had matched but would ask me where exactly on my list I had matched (which is odd IMO), and after telling them, they would say, "I'm sorry." I was like, "you're sorry?" For what?! At first, I would get somewhat defensive and explain that there was no reason for them to be sorry, that I had ranked over ten sites, that this internship had everything I was looking for, etc. My defensiveness ended real quick though, because I simply didn't feel the need to defend myself to these people. Going through this process with everybody from your school can be irritating.
This process is so long, and so emotionally draining, it is normal to have a wide range of emotions after you match. I had friends who matched to their #1 say, "maybe I should have ranked my #2 as #1, oh crap, what have I done?!" I can't think of anybody last year that was 100% satisfied with their "match" at the time. It's just emotional overload.
Once these initial emotions subside, you will start looking for places to live, and will get excited about where you are relocating to. You will start your internship and discover additional things you are excited about, things that you couldn't have known about the site from the interview alone. The time on internship will fly by, and you most definitely won't be thinking, "but if I had matched to my #1 I would be so much happier." These feelings will subside, I promise.