Is that normal for the VP shunt valve to feel heavy at times does that mean its filled up and needs to drain?

It depends... You can always test the integrity of your shunt yourself. Simply give it a pump or two and see how it refills. A recent CT scan will also be more telling as to the need for more or less drainage. That said, I would not over pump your own valve. This can cause over-drainage and even lead to more serious complications such as subdural hematomas.