Lost in thought Could I Be PREGNANT?

Ok I don't know if it went through last time or not but here it goes again. Last month(OCT.) I had my menstal cycle around the 13th this month(NOV.) I have not had it yet I took a home pregnancy test on the 16th it came back negative I have had lots of pressure in lower abdomin but still no period when should I retest? and could this mean I'm pregnant????