I haven't had this problem but I can attest that most people who attend gyms regularly, at least and folks I've met, really don't judge people on their looks and all. If anything, if someone's overweight, underweight, or just out of shape, they have respect and admiration for those people brave enough to come in motivated to make a change in their health and lives.
It's a natural feeling though, seeing others who are all muscular, lean and all that - I'd say most of your aprehension is more due to beginning to work out, basically a stranger in the gym, so proper exercise feels unnatural. With time it'll get better, just keep at it. And not only that but if it's really that difficult to even walk? Sounds like you need to make a change regardless of not having the perfect sized feet or hairline.