My period is 2 days late. not pregnant. no change but started eating healthy and exercising everyday, nothing rigorous. should i be worried?

Repeat preg test: A urine pregnancy test turns positive the earliest a week after conception. A so far 2 day delay of the onset of menses and a negative pregnancy test would be consistent with pregnancy, if ovulation occured later than anticipated. A negative repeat test a week from the first one would make pregnancy highly unlikely as the cause for the delay in menses.