Was this a chemical pregnancy?

Hello everyone...my last periods was on 3rd of june i got a BFP on this. saturday. i was 5 days late on my periods.was really happy as we were trying for an year. monday got my first hcg level done and it was very low 39. doc said either it is early pregnancy or some issues with the growthand asked for another blood test on friday. i had cramps like in periods till yestrday. today i had brown spotting and when i tested with home pregnancy test it showed only a very faint line. am really worried . Hate this waiting. Can Anybody Help me with this. should I prepare for the worst news???