I have to say that honestly I wouldn't worry about it, but I'm a far different loser than you've described. I can be totally on plan kicking it at the gym and it's not unusual for me to stall for an entire month at a ridiculously regular exact same weight right down to the ounce. So I don't think three days is anything to worry about AT ALL. That's not to say I don't understand!
It's very frustrating to stall even for three days, especially when you're used to bigger drops! I do feel for you.
I love your chickie!! 100 lbs lost looks great on you!
ETA: Also, you're smaller now!! It's probably about time for your body to start hanging on its stores a bit more, sorry to say. Now is when patience really becomes key.