Placebo effect and pregnancy

My period is a week late I took a pregnancy test (from the dollar tree) It turned up negative which is fine.  I got my regular cramps and spotted blood one time on Wednesday....then had sex to promote my period into coming which usually works, I spotted one time Saturday....now it's Monday morning and I spotted one time the dark brown blood at the end of one of my regular periods.  If I am not pregnant where is the normal outflow of the blood, still in my body causing some cramping?  The chances of me being pregnant are slim to none as my husband had his sperm count checked a few months ago and was told he does not have a count high enough to have children.  Now my other question is that a week and a half ago I found a baby bird on the ground and brought it in and have been taking care of it 24/7 like a newborn.....can this maternal instinct for the bird have any effect on my body and my period?