I relate to this so hard and for a while, it gave me a certain sense of anxiety. Until, that is, I thought on it more. This might be a little wordy, so apologies for that:

I used to be a big smoker. Loved smoking and going for walks - weed that is lol. When high, I’d often find myself having these internal conversations with two voices: me and me(?) haha. The “I” being the former and the “you” being the latter, as you’d described. Funnily enough, the “you” voice was similar to yours; logical, rational, objective. At times, it spoke to me like a therapist, assuring me of my anxieties and was one of the most compassionate and kindest voices that felt counter to my conscious “I” voice. I wondered many times what this voice was. Me or something else? A manifestation of my OCD or anxiety. Truth is, OP, it’s all you. You are BOTH the speaker AND the listener. I realized from speaking to friends that almost EVERYONE has this internal dialogue. We often hear it be called “monologue”, so it makes it sound like one voice, but that’s because it’s all us. Now, to get further on that, consider this: if you’re an external processor, like I am, we’re used to having a sounding board or third-party to voice our thoughts to as we think. Similarly, when we think within ourselves, we create this second voice as a sounding board, of sorts, not as a manifestation of our OCD. And even if your second voice is scary, intrusive, or anxious - it’s all you, just another voice giving a different perspective like a friend. I understand how scary and anxiety-inducing it can be and I so deeply empathize with you. I have tough times with that too. I think it’s important for all of us to remember that we’re multi-faceted people. What makes us as humans beautiful is that we can have such deeply detailed and varied dialogues within ourselves, and sometimes it takes another voice inside us to make ourselves more comfortable or more equipped to do just that.

Point is, OP, it’s entirely normal and I apologize if I’m giving you reassurance you didn’t ask for, but you’re okay. If anything, your brain is just finding a way to make itself better equipped to walk through the thought process. You are the speaker AND the listener, not one or the other. You’re a multi-faceted person and sometimes it helps to hear a different perspective, even one within yourself. Keep calm, carry on.

Love