Thanks for the query.
After stopping the birth control it will take sometime for regularization of the periods and for resumption of the ovulation.
So the spotting you got could be withdrawal bleeding.
The time of ovulation after stopping the pills vary from person to person. Some women may get in within 2 weeks.
So the possibility of pregnancy
is there but just by symptoms we cannot confirm it.
So, you better go for pregnancy test on around mar 17th, which will confirm the possibility.