Could I be pregnant.?

My last period was on the 24th of May my cycle days never goes past 33 days it's pretty regular. I'm 6 days late as of right now I took a test when I was two days late just to see what the results were but it was neg my boobs has been really tender i get really nauseous after I eat dinner an I've been having lower back pain mainly on my right side about a week an a half ago it kept feeling like my period was gonna come but it still hasn't come I'm not sure when I ovulated or even if we had sex during that time an me an my boyfriend has a lot of unprotected sex just using the pull out method (an I know that's not a reliable birth control) but should I take another test or just wait to see if my period comes..?