Hi and welcome to healthcaremagic,
I understand your query.
There are two possibilities:
1. there is a
pregnancy and this bleeding was either
implantation bleeding or bleeding due to a threatened or
missed abortion. Implantation bleeding occurs around the same time as the expected period or a little earlier and is lighter. Bleeding from abortion may occur at any time. A pregnancy test if positive early and becomes negative later favors a missed abortion or an ectopic pregnancy [ pregnancy in tubes].
2. false positive pregnancy test: rare but may occur due to errors in kits. This is less likely as you have had sex at peak ovulation time and there was no protection.
I suggest that you get yourself examined by a gynecologist for other signs of pregnancy, a
blood test to detect pregnancy and an
ultrasound [preferably transvaginal] for the same. A urine test may also be repeated once again using the first morning sample of urine as it is most concentrated and using a kit of a different company but it would be best to see a doctor and get a proper check up.
I understand your issue and this is the best possible advice that I can offer at this point of time. Hope I was able to help.
Thanks for using HCM.
Feel free to ask any more questions that you may have.
Dr Madhuri Bagde
Consultant Obstetrician and Gynecologist