Period symptoms or pregnancy symptoms.

Why do they both have to be similar?  I usually start spotting on the Monday that I start, but I have nothing yet.  What I do have is...irritability  I yelled at my husband earlier because he told me I should go buy some new pants.  My boobs hurt.  They are a little more sore than normal, but I mean it could just be by chance.  I also feel like I am losing my mind.  I keep losing things.  I lost my key earlier.  It was in my back pocket, and I totally don't remember putting it there.  Yesterday, I lost my cup at work.  I could not find it anywhere...until today.  It was in a box that I moved yesterday.  I couldn't find my phone yesterday.  I thought I left it at home, but actually, I dropped it in my car.  I didn't realize that until I was about to leave work yesterday.  LOSING IT!