stopped pill, ttc

I stopped taking Loestrin mid-August and have not gotten my period yet. I am trying to conceive. I noticed changes last week in my cervical mucus that seemed consistent with ovulation and did have intercourse at that time, yet I am unsure if ovulation can occur that quickly after stopping the pill. How long should I wait before taking a pregnancy test. Loestrin stopped my periods when I was on it, so I have no clue when I am suppose to get my period.