Uugh...stressed 12 dpo bfn

OK..here's the story. my son is 10 months old. I have been breastfeeding and af has not returned. about 3 months ago I noticed some signs that my fertility was maybe starting to return. I started using an opk. finally this month I got a peak reading! we did the bd every day that week. I am now 12dpo...mostly symptom free except a few twinges here and there and a few waves of momentary nausea. I got bfns on hpt dpo 10/12 using fmu. Is it unrealistic to think I might be pregnant, that maybe we caught the first o? I'm going to test again on Monday (14 do)