Congrats on your 1st baby. I was also having light/mild cramping especially when sitting up and down. the doctor told me that cramping is normal, the cramping is from your uterus expanding. i had light spotting in the begining of my pregnancy. of course as being a 1st time mom also i freaked out and called the doctor. he told me that light spotting is normal especially after intercourse. but check with your doctor to be on the safe side.