How you feel about something is actually something that ONLY you control.
Making others responsible for how you feel is a slippery slope. Gives away a lot of power!
Some people just don't know how to read a room. They talk too close. They don't know their breath stinks. They think their advances are welcomed when they are not. And some people think it's their right to share their opinion on ANYTHING with ANYONE. And then they want you to believe their intentions were good and it's your fault for not liking how they've behaved.
And they're right! How you feel about how someone else behaves is all about you.
Her statements about the original poster's weight (and haircolor, too for that matter) were all about HER. And the original poster's reaction to that person's statements are all about the original poster.
Finding a way to be less attached to what anyone says to you or about you (on any topic, no matter what their intentions) will be one of the nicest things you ever do for yourself.
Being emotionally influenced by what others say and/or do will leave you feeling powerless and always dictated by the mood/actions of others. That's awful! (In my opinion, anyway.

And I'm not attached to having anyone agree with me. See how that works?)
Sign my name to PhotoChick's and kaplod's comments above, as usual.
Good luck shaking it off! It just takes practice. Some folks are going to share their unsolicited opinion about anything, no matter what your weight might be. Why wait 'til you're thinner to not care what they say?