Just be really careful about labeling yourself and drugging yourself up. This feeling might just be your way of wanting to change the topic or maybe just end the conversation and move onto something else. You say you like to be social and chat someone's ear off, but maybe you're just changing and that's okay. People's personalities change with age all the time, people's personalities change and their interests change and their direction on a daily basis changes. I've also experienced that sinking feeling during a conversation before as well, but to me that usually just means I'm tired, I'm hungry, they're boring me, the topic isn't really all that interesting, they're draining my energy, or any other number of random things in that split second. So I'm just saying, it doesn't automatically mean anxiety or depression or that you need to up your dose. It might just mean you need to listen to how you feel and not judge yourself for feeling a certain way.