Something strange happened to me during puberty, iin?

Ok so, first of all, this is really important for me so read the details and pay attention for a minute please. Here we go, this is what happened to me: as a kid I looked normal. I was actually really pretty, I had a well-defined jawline and an overall great bone structure. I kept that appearance till puberty started: I now look like I have Down Syndrome. Yes, I know, this is crazy and completely unusual, I talked about this on a forum and no one believed me as Down Syndrome can't develope later in life. While I have seen kids change drastically during puberty, I have never seen anyone change this way. I don't want to but I could provide before and after pictures, I do look like I have Down Syndrome now, but as a kid I looked normal, healthy and pretty. Now my face looks flat and round like that of a person with Down Syndrome, when I was a kid, I had a '' heart face shape ''. And it isn't just my perception, these things are objective and measurable. During puberty, my face started becoming flatter and flatter, and rounder. My face truly looks deformed and weird, but, again, it looked COMPLETELY normal when I was a kid.

Note: I'm not trolling or seeking attention, this post is serious. I'm dealing with depression because of my looks. I don't know what ( and if )something went wrong during puberty, and I can't explain why I was born with a normal face and ended up looking like a Downie, but that's the truth. Does anyone out there have the slightest idea what happened to me?