For how long can you be pregnant and menstruating at the same time? I have like about four months that I have sex without protection and the last three months I got my period exactly on the day it supposed to be, but this month I haven't got it period and

Anytime . Anytime you miss your period and you are sexually active, there is a chance that you could be pregnant. To answer your question, some women can have one cycle while pregnant, which is not a real cycle but rather bleeding due to implantation of the embryo into the uterus (womb). If in fact you are pregnant, your doctors will be able to tell you exactly how far along you are with a simple ultrasound. All the best.