Chemical pregnancy?

Hi ladies, i got faint positives in the lead up to when my period was due along with all symptoms from my first pregnancy. I'm now 5 days late so decided to test again to see if the line got any darker but i got a bfn☹️ i had really bad lower back pain last night and went to bed in agony convinced i would bleed through the night, but nothing. Could this be a chemical pregnancy? and if so, is it just a waiting game until i start bleeding? thank you in advance💖