My husband is straighter than a yardstick, and people have questioned him. Why? Because he is a good cook, doesn't like watching sports, and loves cats.

Hobbies, body language, appearance, etc., none of that makes a person gay, straight, or anything in between. The ONLY thing that decides whether a person is gay or straight is who they're sexually attracted to. But I suspect you knew that.

Also, ask anybody who's ever been bullied in school, and I'll bet most if not all will say that this bullying includes being accused of being gay. Tossing around homophobic slurs is a very common bullying and harassment technique. Which I think sucks. Could it be that people who are questioning you don't really think so, but are just saying it to be jerks or intimidate you for some reason?