First time since coming off pill that my period has been late! Wishful thinking?

Hey! So I've been off the pill for 4 months and had no success with falling pregnant. My periods have been regular like clockwork and always come every 26 days. I either ov'd on 31st December or 2nd January. Had sex the 30th and the 2nd...so far my period is 2 days late and doesn't appear to be coming other than sore breasts. Took a HPT yesterday and got a BFN how long should I wait to take another? Or does it not sound like I could even be pregnant?