The average menstrual cycle is 28 days from Day 1 to Day 1 of your period. However, anywhere from 25 to 31 days between periods is considered a normal menstrual cycle. The best thing to do when you suspect that you're experiencing abnormal bleeding or menstrual cycles is to consult with your health care provider.
During interphase, the cell is preparing to divide and is actively synthesizing the required components. Originally and inaccurately referred to as the resting stage, the interphase is actually a period in which a considerable degree of activity is taking place on the sub-cellular and molecular level.
Interphase is not a part of mitosis - it is a part of the cell cycle. Interphase and mitosis are separate events, but mitosis depends on interphase. In the three stages of Interphase (G1, S, G2) the cell is enlarging and synthesising both the DNA within the nucleus as well as organelles.