pregnant? & is it too early for a test?

Maci
I'm wondering if i have a possibility of being pregnant....i'm on cycle day 18 & we had unprotected sex on July 5th. the last day of my period was July 3rd. glow said I was supposed to start my fertile window on July 10th but I started having changes in my bbt & cervical position on the 8th or 9th. do you think I could be pregnant? & would it be too early to take a pregnancy test? my next expected period is supposed to be July 29th 
​please help