Worried ANd Confused

So Im On CD 60 No AF At All An 2 Weeks Ago I tested An Got A BFN So Im Going To Try An Test Tomorrow Morning, My Friends Are Saying Since I Went To The ER Like Back In July The Last Week Of July And Blood An Urine Was Negative, That Maybe My Hcg Level Is Either Low Or Not Going To Show Up And I Should Get A Ultrasound Im Having All The Symptoms, has anybody ever had this happen before?