Help please, advise needed!!??

Me & my 4 yr boyfriend are ttc on our 2nd child. Weve been trying since ive gottan my birth control taken out on the 27th of August. My doctor told me I could get pregnant soon as I take my birth control out but nothing. Ive gottan my first period on September 25th it lasted 3 to 4 days. Is my body regulating if so how long? Or could I be pregnant? Or could I be ending up pregnant by the end of this month since my period was short & ive always had regular periods. Idk what the inplanon does to your body im confussed. Help please?