Help! lol

I just wanted to ask if anyone else has had a similar situation.

We have been TTC for a little over 2 months now. I’ve had a consistent period for years. I always start the morning of the expected date or the afternoon prior to what was expected. Today I was suppose to get my period, but it hasn’t showed up. I took a pregnancy test this morning and it was negative. All the ones I’ve tried up to this point have been negative.

This morning I walked my dogs (like normal) and got nauseous around 1.5 miles. Which is not normal for me around my period. Am I just overthinking it? And if not.. what should I do?