YES! This happens all of the time to me! Most people will actually admit to not having recognized me, though. I'll say, "hi" to someone and they'll give me an awkward "hello" back, then about 20-25 seconds later they're like, "OMG it's YOU" lol!
It used to be somewhat offensive. I know it's not their fault but I'd like to think that I still look like the same person. When I was heavy, I had high self esteem and I especially liked the way my face looked. Every time someone doesn't recognize me, I start to worry that my face has changed for the worse.
However, I think people just look at the whole picture. When you say "hi" to them, they try to match you up to someone they know; they look at the WHOLE you, and when the new you doesn't match anyone they know, they need to think harder and look more at the specifics rather than the general body.
Congrats on your progress, apparently it really shows!