confused...

Ok ladies, so my AF is 3 days late today..I took a test and it came out negative....I'm confused, my period has been irregular before, due to the depo, but the last 8 months it's been regular. I've been having cramps, fatigue, and some nausea. should I wait a couple more days to retest or should I go to the dr and have blood taken? when I was pregnant with my daughter 6 years ago, I had taken numerous tests and all of them came out negative. I went to the dr at 6 months because i thought i had pulled a muscle, and they did a blood test/ultra sound and I was pregnant. I didn't have any symptoms with her at all. I'm so confused.