Hello, I would be happy to help you with your question.
This is a tough situation in terms of telling exactly where you are in your cycle. In the first year after coming off of the depo shot, you might experience some significant cycle irregularity. As you know, the depo shot lasts for 3 months, so if you just got the shot on 2/12/2013, then it is still in your system for a total of 3 months. The bleeding is more likely related to breakthrough bleeding
on the depo shot than it is pregnancy
. Nonetheless, I would check a pregnancy now and repeat it in 2 weeks just to be sure.
I hope that this helps and good luck!!