Im 9 weeks pregnant?

im 9 weeks pregnant i just had a sonogram about 3 days ago and the baby i guess is growing ok, but in the past 2 days my haven't been as sore, like they usually have been, during the sonogram the nurse told me she could see the baby heart beating, i was just wondering if that is true and if she was seeing the heart beat is my baby ok, also ive been having cramps, similar to menstral cramps, but no spotting, i had a miscarriage like almost 2 years ago, i just need to know should i be worried?