I feel for you. It's horrible to think people are looking at you and judging you. But if you sit with that thought for a bit - it doesnt really matter one jot if they are. They might think, "she's chubby" as you walk past. And then ten seconds later, "I like that girl's sunglasses.... I wonder if the coffee kiosk is open... I'm really hot can't believe it's such a sunny day."
Your weight, or any other aspect of your appearance, makes almost no impression on these complete strangers you are walking past. Your arms, I would pretty much guarantee, will not raise even a flicker of interest.
I read something a little while ago about fear in children. That the first time you do something scary it feels awful. The second time it still feels awful. But over time it gets a little bit less scary each time; and even if you have one or two bad experiences, they don't stand out much if you have a hundred fair or good experiences.
So I say: take a walk every day. Drag your DH out with you; go on your own. Go early sometimes and experiment wearing slightly more revealing clothes when there are fewer people around.
PS you're going to get more funny looks I'd you're dressed up in six layers of clothing on a hot day.
As for your DH -is that absolutely the sum total of everything he said? You poured your heart out and he said, literally only, "well do something about your weight"? If that is all he said in response, that's pretty cold but also, perhaps he doesn't know how to fix things (men like to fix things). He wants to enjoy being outside with you; he has to drag you out for a walk and you probably evidently uncomfortable.
And maybe he IS a bit embarrassed. Or maybe that's you transferring your feelings. Or a bit of both.
But all these feelings can be managed and controlled, you just need to practice and learn to be comfortable in your own skin.