It's almost been a week still no period what going on.

My period should have started last Saturday so it has almost been a week, my breasts were sore a week before my period which always happens and stop right before my period was supposed to come but it has not shown up. I have been noticing that I have been breaking on my face which never happens to me when I have my period. I am having mild cramps,headaches and I went to the pet store I couldn't stay in there reactor the smell and the funny thing is I go to that pet store very frequently. What's going on anyone else going through this.