Faint postive on 2 tests blood test came back negative

Me and my fiance had been trying to concieve for about a year and i have, he just passed away on valentines day. I took some tests this passed weekend just because i had them both came up faintly positive, the first one too light for a photo then this one. I went yesterday to get a blood test but they said there is no hcg, im so confused because ive been having all the symptoms but just chocked it up to stress anxiety and my pcos. Any ideas?