neg blood test

I was having extremely bad sharp shooting pains last Friday and ended up at the ER. I was told that my blood test was negative at 9 dpo. I'm feeling better still having some cramping but still have this feeling that I could be pregnant. Has anyone had a negative blood test and went on to have a positive one in the same month ? Glow says to wait and test til tomorrow. I'm just nervous about using a test if the blood one said negative. Any help would be great. Thanks.