Ive Been 6 Days Delayed In My Period. My Period

Ive been 6 days delayed in my period. My period should start on the 28th of October. Ive done pregnancy test on oct 31 and nov 1 but results were negative. I have signs such as breast tenderness, constipation, and sometimes cramping. But there was no spotting that i experienced. Last Oct 4 to 10, i was hospitalized due to typhoid and dengue. October 10 night when i went home, we had intercourse with my boyfriend. Could that mean im pregnant even if the pregnancy test was negative? Is there a possibility that may recent hospitalization caused the delay? Im on my 35th day of my cycle and my period hadn't come. Pls help.