Hi,
Thanks for the query.
The possible causes for your bleeding are :
-Impending menstrual flow.
-In case of
pregnancy, there is possibility of
implantation bleeding or
miscarriage.
The possible other causes of bleeding in early pregnancy are : http://srsree.blogspot.in/2013/06/causes-of-bleeding-per-vaginum-other.html
-
Hormonal imbalance leading to intermenstrual spotting.
Dark color of the blood usually indicates collected blood.
Once go for pregnancy test.
If the test comes negative, the possibility of pregnancy is less.
And you may get periods soon.
In the next cycle, you can track the ovulation and can plan intercourse around that period.
For more details : http://srsree.blogspot.com/2013/07/infertility-1_8.html
This will increase the possibility of pregnancy.
Take care.