sore nipples a sign?

I have tender nipples this morning. I NEVER get sore nipples any time during my cycle. Not even before af. This is so out of the ordinary, I'm wondering if it can be an early pregnancy sign. The thing is, I'm only 4dpo max. It's to early for any pregnancy symptoms, right? I also was nauseous last night for no reason. Has anyone else had symptoms this early? Is having sore nips a sign if I never get that usually?