->PROTECTED<- SEX = Pregnant???

---------------------------------------------------My boyfriend & I had PROTECTED sex on 4/28/17, two weeks ago. We made sure to switch condoms every time he'd come out and after cumming. He'd wipe the cum off with a tissue then put another condom on. It is now 2 weeks later when my period is supposed to come. I usually get my period the 18th of every month, but last month I got it 4/12/17 so earlier than usual. My projected start date for this month is 5/11/17. I have had very minimal cramping compared to the cramps I get when I'm about to start my period. I took a pregnancy test on 5/9/17 and it came out negative. 

I'm wondering if there is still a chance that I could be pregnant or if my period is just a little late and will start the 18th instead of the projected date, the 12th, since last month it came early. However, today is the 31st day from when I last got my period. I'm worried that I may be pregnant but we were extremely safe. Is Mother Nature playing a trick on me?? Lol :( Thanks for your help!