What are the chances of pregnancy in this case?

Hi, before you all start I am having a blood test on wednesday but would like some advice/answers anyway. You know whats its like wanting to know but not wanting to test at home in case of a (-) result, well I'm 2 weeks late on my period. If I was pregnant how many weeks would I be gone? Im having sore , and a lot of tiredness but I'm usually tired anyway. My period is like clockwork so I'm more swayed to thinking if its not pregnancy what else could cause these types of symptoms. Also what symptoms did you have 2 weeks after missing period. Thanks for your help