I agree with the above. You would have to be less than 4 weeks for it to be too low on a pregnancy test. Symptoms mean absolutely nothing and can't be relied on. If you feel like the tests are false negatives, see a doctor for a blood test.
I'm going though the same thing. I did have a faint postie though. I think it's probably better to just see the doctor. that's what i'm doing
Unless you JUST got pregnant within the last few weeks, you should be far enough along that the HCG in your system would be detected by a pregnancy test.
When you miscarried did you have a natural one or a d & c?