ChicaSica

I am 6 weeks post op...2 weeks post op i received my monthly cycle on time as normal prior to surgery and spotted till feb 5th. I have been sexually active with my boyfriend. I should have received my monthly cycle this past feb 20th and did not. it is now the 8th of march and still no aunt flow. I have taken a few pregnancy tests only to have them be negative. Could i be pregnant? Cycle just completely off? Has any one had this problem? i dont see how my first cycle after surgery after losing 18lbs and i received it on time as normal; and now my 2nd cycle post op has yet to show.