So if this is bullying, as some people here have suggested, I don't have any great advice for you; I've always been an alpha dog, male or female, so issues with bullying haven't really come up. That being said, whether it's bullying or not, it needs to be addressed immediately, or its likely to start a domino effect. If it's not bullying and simply a lapse in memory or whatever, it's best to remind people that your birth name is not in any way associated with you and that if they want your attention, they have to respect you with your real name, as Luke. I hope it isn't ill-intented misgendering/naming, but best of luck either way, bro!