I almost always take whatever they say as a compliment and it usually is. If there are two ways to take something someone says, pick the one that is the most complimentary to you. It will make your day better, I promise. Look for the good in their comments. In their own roundabout way, they are showing you their, envy, or often revealing their own self doubts. Unforunately, getting worked up about the words of others, reveals our own self doubts.
Most people have very little weight behind these off had comments. It is our perception of them that adds the weight and allows the dreaded "Rent space in our Head" issue to arise.
All the knicknames, the quetions "Are you a wrestler/football player etc, or even just "Who are you, you look like somebody" are acknowledgement that they have recognized you have put in more than average work and look different than the average guy.