Thanks for the query.
The possible causes of your bleeding are:
imbalance causing inter-menstrual spotting.
-In case of pregnancy
that can be implantation
Though some of your symptoms are suggesting the pregnancy, but it is early to comment about the pregnancy.
So you wait for your expected date of periods and if you miss the periods, go for pregnancy test after 4 to 5 days.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429