No Period, Negative Pregnancy Tests.

I came off of birth control in Dec. (after being on it 7 years) and my Doctor told my husband and I that Feb. would be my best  fertile window. (I'm 25 by the way) Here it is Feb. and I'm a week late... I took a test Wednesday and another Friday, both negative. Now I'm just frustrated. I know that it could take some time to get pregnant but not being regular is driving me crazy! My acne is really bad and I've had weird things happen to me like dizziness and fatigue but nothing severe at all.