2 days late and still a negitive pregnacy test?

So on Nov. 20th I found out I was pregnant and them started my period on the 21st. Went to the OBGYN and he did an ultrasound and said everything looked norma, also did blood work and it went back down to normal levels. He said I had a chemical pregnancy and that was that. Well now a month later and I'm late, I'm never late always right on time to the day. I know this cause I've tracked my cycle for 3 years now. I took a test yesterday and it had a very very faint positive line, then I took a digital and it said not pregnant. Now I would have ovulated on the 7th but I think I might have later cause I had a clear discharge like around the 11th. What do you think is going on???? What should I do????? I have a ton of pregnancy test but I dont' want the disapointment in taking them. DO YOU THINK I MIGHT BE PREGNANT???