So I Got My Last Period On August 12 And

So I got my last period on august 12 and I started the mini pill on the 13. My boyfriend and I had protected sex with a condom on the sixteenth of august. Then I moved across the country to go to college as a freshman. My period ended on the seventeenth and I have only been late taking my pill once. I have never been on any kind of birth control before and it is now the twentieth of September and I still don't have my period. My typical PMS is tender breasts and nausea and headaches. I've been feeling slightly nauseas but no breatstenderness or weight gain. I'm working out a lot more too. Should I be worried?