Depo provera is unique injectable longacting contraceptive
which usually act for 3 months duration, but in many women on depo provera menstruation
may stop during and after injection, usually after use for more than 1 year. peroids usually returns to normal after stopage. menstruation depends on ovulation which is stoped during depo provera contraceptive, and pregnancy
is depends on ovulation so if you continue to have amenorrhea
or lack of peroids consult your gynecologist, and as your age is just 21 years dont worry and hurry for pregnancy.