Period but Pregnant. Now low Progesterone. Help!!

I started my period on June 28th and lasted ~5 days. It was normal except for brown spotting after my period was over. I went in today for an HSG test because my husband and I have been ttc for 16 months and we figured my tubes were blocked. But it turns out that I am pregnant!! I had NO CLUE, NO SYMPTOMS.

Blood work came back and the doctor said that I am positive for hcg but low in progesterone. I am going back on Monday for more testing. She said that I need to be prepared for both scenarios. Has anyone ever experienced this??