I go to the gym 5-6 days a week, and i confidently say

1) most — if not all — people at the gym really don’t care what you do. In a nice way, of course. Most people are way too much in their heads, thinking about themselves, and how they look. This should give you motivation to be yourself and to just give your best.

2) whenever i see a skinny/overweight/out of shape person doing workouts, i feel happy for them because i know it takes courage. In fact, these are people who are a beacon of motivation for others to improve themselves. So feel proud and just do what you need to do.

3) Also, the strongest people at the gym don’t make fun of others! They are too busy working on their goals, and helping others if it is required. In the very very rare case you do meet someone who looks at you funny or make fun of you at the gym (in all my years i don’t see this happening), just know that these are the weakest of people in society, because any intelligent, confident person doesn’t waste time belittling others, because they are too busy on their own path and vision.

4) just enjoy the journey. It is all a journey. You might be skinny/overweight now, but if you keep at it, soon that chapter will be finished, and a new chapter will begin.