Your widal test is negative for typhoid. In Widal test important factor is the level of the O and H agglutinin titer levels. If this number is below 1:160, it is normal. If, however, it is over 1:160, you may have typhoid fever or another salmonella related illness. But even after this negative result you can have typhoid. As Widal test report can produce a false positive for typhoid because it cannot interpret the difference between a person currently ill with typhoid and one who has recovered and is a carrier or one who simply has been vaccinated against the disease. It can also confuse the diagnosis with other salmonella-type conditions such as malaria. So get a Blood culture done. Then start any anti biotic. Recommended antibiotic is tablet cefixime 400 mg 1 × PO × OD for 5 days