You won't get sick from expired heavy cream as long as the expired heavy cream does not smell bad or has mold or a bad taste to it.
Heavy cream is usually good in the refrigerator for up to a month without going bad.
Just because the heavy cream has expired doesn't mean that it's bad or unsafe to eat as long as it smells good, has no mold in it etc.
If it smells sour or has mold in it then throw the heavy cream out.
If you do eat bad heavy cream that has expired you'll experience symptoms such as vomiting, diarrhea, stomach cramps etc.
If you don't think the expired heavy cream is still good then just throw it out and do not risk your health.