Is it possible for me to ve concieve a month later then what my OGYN told me?

I roke up wih my ex about 2 weeks after w hd forthe second time and started seeing smeone that aiwas interested in ad had with him also. Now i dont know witch one the father and take it evn worset was like2 weeks part and in two diffrent months ad hd 3 diffrent due dates.