Question: Possibly Pregnant Again?

September 13 I had a missed miscarriage with my daughter at 13 weeks. I had my d&c the day after. My obgyn informed me I am fertile after a miscarriage. My daughters dad & I had intercourse unprotected but he did pull out. Last Tuesday I had brown spotting when I went to the bathroom and also some cramping that day and it would've been a week exactly since intercourse. Since then I've had some mild cramps and bloating, I'm pretty emotional and quite tired. My obgyn said it is possible to get pregnant from precum especially since I am fertile currently. Is this at all possible or has any other mommies had this happen and they DID end up being pregnant?