Talk to Gynecologist on Delay In Menstrual Cycle

Hey ASALAMOALAIKUM, Im a mother of 2 normal delivery hoi both, around 18-20 of every month almost meri menstrual cycle start hoti hai but august me mujhay start nahi hosakay matlab last june me aye hain, i also had a check through strips k kahin conceive to nahi krlia but the result was Negative,please can u help me k kia karun? Any medicine jis say start hojaen? Ya phir kuch aur ?