Anyone have irregular periods on topamax?

I take topamax for a mood stabilizer. I just started first week of February . I am 4 days late on my period....and negative pregnancy tests. I had unprotected sex with my husband on February 18th and he came in me...I don’t know what’s going on. My period isn’t ever this late 🙄😩 I also have a 6 month old baby...