Does Delayed Menstruation After Stopping BC Pills Need Medical Attention?

4 months ago, i stopped taking birthpill. i have after that 1 time a menstruation 2 months to late. and now i'm am 2,5 months over time. what should i do, go to see a doktor? ore wait till i get a menstruation. i think i cant be pregnant because i only have seks wenn i had the first time menstruation.