new to this;

I never thought I'd post in a forum but I suppose I've gone through quite an interesting event. January 1st of this year I found out my fiancé and I were expecting. I took 4 at home tests and went to the nearest doctor to take another (urine) test. All 5 came back positive and got confirmation paperwork stating I was. A week after, I got my period and went back to the same place that confirmed my pregnancy and was referred to the ER to see what was actually happening. I got a blood test done and was taken back to a room to speak with a PA who had eventually told me that I never had the HCG hormone in my blood and also told me that it was not a miscarriage....does anyone have any answers as to why this happened? I've since been heart broken and we have continued ttc, but I still feel crazy...