Is Pregnancy Possible After Stopping Depo Shot?

HEY I AM 18YRS OLD AND I HAVE GOTTEN MY FIRST AND LAST DEPO SHOT ON APRIL2010 AND I HAD TO GO BACK FOR THE SENCOND SHOT ON JULY 21, 2010 BUT DECIDED TO BECOME PREGNANT. TWO WEEKS LATER WHICH WAS ON AUG.05.2010 I HAD A PERIOD BUT I NORMALLY HAVE HAD LIGHT PERIODS ALL MY LIFE. SO EVER SINCE THEN I BEEN HAVING UNPROTECTED SEX. CAN I BE PREGNANT AT THIS DAY WHEN I AM HAVING ALL THESE SYMTPOMS OF PREGNACY???