I just had a baby 6 months ago and I think I am pregnant again. I had some spotting when my period was due but it stopped that day and has not returned plus my boobs started lactating I have had an ultrasound and a urine test the doctor told me he does not think I am pregnant but when I went for an ultrasound I had I thick lining around my uterus and she thinks I am pregnant. Could I be lactating from having my daughter or am I pregnant?

Could be either way. Had your periods resumed a regular pattern prior to the light spotting? You could wait until your next period would be do and see what happens, try another home pregnancy test in maybe a week or so, or mention what was said at the ultrasound again to your doctor and ask that a blood test be done.