Safe days

Recently my boyfriend and I had unprotected sex on my last day of fertility (Day 16). I’m now 5 days from my cycle and my breast are crazy sensitive and I cant sleep worth crap. I read about different things that occur during ovulation and the days that follow, and also that most of the symptoms I’m dealing with are pretty common for both pregnancy and AF. So should I wait until my supposed start date to do an at home test or now (a week after)? I regularly smoke cigarettes but since I’ve been suspicious its hard to touch them and I just want to be sure before I do anything that could harm a possible baby.