6 month old slowly bobs head up and down

I tried to find anything online to help me but everything just talks about shaking their heads back and forth and that’s not what’s happening.

I noticed the last couple of days my daughter will randomly start to slowly bob her head up and down, like she’s nodding but kind of in an exaggerated way. She seems very focused on it when she does it. At first I thought maybe she was tired but even after a good long nap she was still doing it once in a while. She’s acting normal otherwise and other than a runny nose because the poor thing caught a cold I had last week and some pretty excessive drooling (I think she *might* be teething) she doesn’t have any other symptoms.

It’s kind of freaking me out. I can’t help but think she’s having a seizure or something. My partner thinks I’m being ridiculous (I do tend to freak about every little thing when it comes to her, classic first time mom). We have her 6 month check up on the 15th, but I don’t know if this is something I should take her in for before that?

Any experience with this? Would you take her in before her appointment or wait it out?