Having both the urine and the blood test
negative after a missed period almost rules out a pregnancy
. You should get a trans-vaginal sonogram to see the local pathology. It could mostly be a hormonal
imbalance and you need to get investigated and treated for that as it has already been for three months and if you wish to conceive now, you should get treated for that also. The cause of your previous miscarriage
should be identified. Consult your gynecologist for further suggestions. Wish you good health.