My period is 17days late am i pregnant?

Possible: It's possible especially if you've had unprotected sex and even more so if you had unprotected sex around ovulation (mid cycle). You should definitely do home pregnancy test. If it is negative, however, you need to repeat it in a week or so. If still negative, wait and see if your period may come when it is due next time. If still no period, seek local care.

Use a pregnancy test: to know. Reasons for missed /late periods: low body weight, obesity, marked weight gain or loss, over-exercise such as in endurance athletes, breast-feeding, stress, illness, eating disorders (bulimia or anorexia), travel, hormone irregularities, drug use, medications (i.e., birth control) or med problem (polycystic ovary syndrome or Asherman’s syndrome. #1 reason is pregnancy.