Rapid jaw growth?

I'm an 18-year-old male.
A few weeks ago when I arrived home from university I noticed that I looked different in the mirror, after looking a bit more, later, I thought that only the left side of my face had changed. It looked more filled-out. My sister said I looked like I'd gained weight because my face looked 'more round'.
After a few days of examining on and off I concluded it was my jaw that had changed shape; it had grown on the left side. I'd been looking at myself in the mirror every day at university so I'm not sure how I only noticed it when I got back. I also noticed that my left thumb was a bit bigger than my right one, which hadn't been the case before.
I came back to uni last week and have noticed the same thing happening to the right side of my jaw over the past week, and it now looks the same as the right side, and now my right thumb has grown too and looks as big as the left one.
I know that I should still be growing at this age but I'm alarmed at how quickly it happened, and I'm worried people will notice and think it such a rapid change is strange. It seems unlikely that it's just normal growth and I'm quite anxious about it.