Those two girls are a pair of losers.
Think about it. They're young adults, and their level of maturity is so advanced that they actually believe it is appropriate to belittle strangers, express their narrow minded opinions regardless of others feelings, make simplistic judgements based on a person's size and grocery cart, and act in an aggressive manner toward others.
They may have (for the moment) hurt your feelings considerably, but think of what tomorrow holds for those two with what you know about them. Do you think they have decent jobs with that level of maturity? If they have a job at all, do you think that they are going to hold it for long with the behavior they demonstrate? Can you imagine how they interact in their personal relationships (they've probably had at least one scrap in their friendship since they picked on you, a boyfriend fight, and an argument with family judging from their high quality relationship skills.) By the time they go to bed tonight, they'll have probably forgotten about you, and accumulated a whole bunch of their own person hurt brought on by their own lousy behaviors and attitudes.
Large people do have lousy moments in their lives due to the acts of some lousy people. But take satisfaction in the fact that lousy people earn and recieve lousy lives. There is NO WAY that a pair of 21 year olds with that kind of behavior are headed anywhere else but toward a few really tough years of learning just how well in life they can do with bad behavior, misplaced self importance, and toxic attitudes.
If you let thinking about those two affect another 5 minutes of your life, make sure that you keep in mind that while they made you feel low, they're rapidly on their way to lows that will hurt even more than the sting you took today. I know yours still stings, but I can see that you are confronting it and healing it and it is passing. You obviously know who you are and that their words were incorrect, stupid, and inappropriate. Those two are still on their way to some hard learning before they ever get to that level of self knowledge.
By the way - 60 lbs? Wow. You are getting really close to the 2's. That's really cool. Be sure to spend some time thinking about that today, too.
Lynda