Education:Am I Pregnant?

I%26#039;m not sure what to think about this...I tested 3 times and they came back positive and around the time I was suppose to start my period I started to bleed dark red with tiny clots for about 3 days same as my normal periods are but this one was much lighter and in spots then at the end a little brownish. So after that I retested myself again and came back negative. I was drinking lots of water and taking my prenatal because I thought I was pregnant. Am I pregnant and could I have possibly diluted my urine?? Or is this a Chemical Pregnancy? I don%26#039;t have a doc appt. till the begining of next month so I was wonder what you might think.