Hello I am a 26 year old. I have always been exaclly 28 days then the last couple months I have been four days late... this month it hasn't even came. My breasts are sore... I did have sex and it was protceted by a condom. I took a walmart pregnancy test and it was negative. I do think I have a uti so idn if that will hold it back... I do know when I was pregnant before I always had a uti. Can someone give me some advice... thank you