Your history suggests that you are going through hormonal
imbalance and the reason for that should be investigated first. With so many negative pregnancy
tests after such a long period of amenorrhoea, it is unlikely that you are pregnant. Recent pregnancy and delivery disrupts the cycles for quite some period. Other causes that are likely are weight disturbances, stress
, infections, medications, hormonal disorders etc. Please try to maintain a healthy weight and do some regular daily exercise. Eat healthy and drink lot of fluids. Please get further support from your doctor. Good luck.