Thanks for posting,
Well I do not think you are pregnant if you have been taking the pills as indicated even though it will be wise to conduct a pregnancy
test in about a week's time just to be sure that pregnancy is not the cause of your amenorrhea
Pills are hormone based and can alter the concentrations of your natural hormones there by leading to menstrual irregularities. Since you changed abruptly your initial birth control and introduced a new one, it is possible that it is the change that lead to this. Menstrual irregularities eg, spotting, breakthrough bleeding
or amenorrhea can occur during its use. Most of these side effects are mild and usually disappear after a few months of contraceptive
So I suggest you worry less as stress
on its own can lead to menstrual irregularity.
Hope this helps