Had protected sex on day 7 and ovulation day was on day 12. Went trekking on day 13. Supposed to have my period on 2 days ago. Can I be pregnant?

Maybe. Maybe not. If worried, just do a pregnancy test. A urine test done correctly gives a reliable result 3 weeks after sex (3 weeks after when conception might have happened). If done sooner, a positive result is likely real, but a negative result may be due to testing too soon, and therefore lead to a repeat test.