Was I ever pregnant?

I have PCOS and over 3 weeks I continuously took pregnancy tests all very positive!  This week I didn't take one the last one I took was 7 days ago...today I said to my SO that I just don't feel pregnant anymore but had no cramping no spotting nothing I just didn't feel pregnant.  I went and bought a few tests both negative and went to hospital.  Hcg blood said 0 and urine negative and ultrasound saw nothing.  Was I ever pregnant to begin with?? Is this a chemical pregnancy? We are devastated has this ever happened to anyone else?