I am so so so UPSET

I am not due for my period until the 20..I have taken several pregnancy tests yesterday and they all came out positive..today..this afternoon I took a couple and they were all negative..I have mild cramping..my breasts are slightly sore..I knew I took those tests too early but I was so excited when they came back positive. I even went to the Dr and they did a qualitative blood test and it came back negative..what's going on? Could I still be pregnant and my hcg levels are just to low? The following pic is on of the positive tests I took