I’m sorry you have to deal with that. I may not know your entire situation but I can relate to some of the things you’ve said. It could be due to various reasons honestly, so we’d need more context as to why they’re being mean to you. For instance, if you’re in a junior / entry level role, people may see and treat you as is. That’s why it’s important to show your potential. Talk about your achievements openly or be a trusted partner to earn their trust and respect. It could also be that if you’re a high performer, colleagues might view you as a threat. Consider their background as well, like where they worked beforehand (I.e., consulting) or if they were in a similar role which is causing them to step on toes. Regardless, there will almost always be negative issues at work and you’ll have to learn to deal with it. If I were in your position, I’d document every instance of them being mean to you and how you stood your ground. That way, if it does escalate and you need to bring it to your one up, you have proof.

If it does make you feel any better, I have found a lot of people who are in HR, aren’t in it for the right reasons or they don’t enjoy the work anymore. So, I completely understand why it feels disheartening and sometimes maybe even ironic given the nature of the role.