I agree with the above. My DH and I were using the withdrawal "method"... see profile pic for the result of that lol. But we wouldn't have it any other way... we are so in love with our little oopsie baby!!! :oD
Withdrawal is not a great form of birth control. So yes, you certainly could be pregnant. Try another pregnancy test on the day your period would be due, or see a Dr. for bloodwork. Also, keep in mind that mid cycle spotting is not uncommon and happens to most of us from time to time. The light bleeding could just be the start of it. Good luck.
Okay, well if you used the withdrawal method knowing that you were ovulating, there is a chance you could be pregnant. Many people get pregnant that way. With that being said, you could be having implantation bleeding or just spotting leading up to your period. For some reason I spot 6dpo until my period is due whether I'm pregnant or not so spotting is very normal for me. Test the day your period is due it you don't get it. If you don't want to get pregnant, I suggest using a different method during ovulation.