Ttc #4...is my chance gone?

i have three beautiful boys. my husband and i are ttc #4. i think that we bd on the right days. i guess i kinda feel pregnant, but i am not sure. i ovulated 6-7 days ago. last night, i had some bleeding, it was only a little. so i figured that i wasn't pregnant. i didn't ever bleed with my other pregnancies. are my chances of being pregnant gone? i am not due for my period for another week.