How To Differentiate Between Normal Period Symptoms And Pregnancy Symptoms?

hi sir Iam bharathi.I have pcod problem.I am taking treatment.every month pimples came in my face and leg pain and i feel chest weight&pain before 10 days get period.my question is if i missed period but the same syntoms of pimples,leg pain.then how to know wheather i conceived or not.if i conceived also same syntoms will come or not.