It is OK to be kind and gracious...but also to be protective. I am a single woman and when I am out, like having coffee, or just carrying packages in the parking lot, etc., there will be the oddball weirdo who comes up and tries to start conversation. I now have a rule that I don't talk to strangers (especially male) who come up to me in public. In your situation that is just what I would have said to that person. I use my intuition and I don't talk to people who creep me out. If someone continued to talk to me when I made it clear I wanted them to leave me alone I would get up and notify the management. I now have no problems "not being nice" and ignoring someone. The truth is... coffee houses like Starbucks and fast food joints attract a lot of lonely, weird people, I am sorry to say this but it is my observation.

It may not be your weight that is the problem, but that you feel invested in acting "nice" even when you are feeling bothered by someone. I used to be approached more when I carried an "open" attitude. Now I go out with a psychological protective bubble around me and I am not bothered much by weirdos and it actually makes life more pleasant. I avoid coffee places that I know are kind of like watering holes for weirdos. I select places that are a bit more upscale. Starbucks used to be a favorite but now I avoid it completely.

It may help to set up psychologically healthy barriers. I feel that when I am out I deserve to feel safe and at peace. Just because I am a woman out alone doesn't give others the right to see me as approachable. I certainly don't want strange men coming up to my table and talking to me! I wanted to share so that hopefully you might feel less alone in this. Also, when I was young and single I was constantly approached in public. I worked out and was very buff, dressed fashionably, and looked pretty good. So then the attention from men felt sexist. It was tiring to get attention and inappropriate remarks from strange men and wolf whistles from them, too! The truth is that women of all ages and sizes are bothered when in public. It's not fair. We need to fight back!

Going to the meetup dinner sounds like an excellent suggestion...or even joining an exercise or walking group. You are going in the right direction. The CBT group also sounds excellent. These are all great ideas. Good luck.

PS The opposite of unwanted attention is that I also get positive attention when out. People always make sure to open the door for me which I find very sweet. One time it must have appeared I was struggling with my grocery bags because a young girl came up and asked me if I needed any help. I didn't, but it felt good that she noticed. I think it is important to dress nicely and be well-groomed as these indicate to others that one is healthy, and confident.