Yes ma'am, it is very normal! It is your uterus stretching and maybe even a few early Braxton Hicks contractions (totally normal). If you check out the right sidebar you will see something that says I AM................ Pregnant, Trying to Conceive, Maybe Pregnant. Click on PREGNANT.
Yes it is for the first few months some people still have menstrual cramps when there period is due. I did until the second trimester. As long as you are not bleeding or passing any clots and it's only happening when AF would have been due I wouldn't be to concerned. If your too worried call your doctor it never hurts to check.