Have you confirmed that all metrics are collecting properly? Is the storage profile service functioning properly on the vCenter server (validate in vCenter Health Status)? Take a look a see if the datastore > disk space metrics are collecting properly, as they're dependent upon the storage profile service and won't collect properly+calc planning #s if the service isn't functioning properly. Another way to validate this is open vCenter and ensure you can view all of the datastore data in the "storage view" tabs.
On the capacity planning #s, there is more to look at then just the days remaining. If you read more in to the #s you'll see 'why' there are 0-days remaining using the tables within the planning views. Do us a favor and upload a "virtual machine capacity" report, which will contain the policy settings and output information necessary to understand why you're no capacity/time remaining. Also attach a "planning summary" report too so we can have that perspective.
One more thing - do you have RDMs?
If you find this or any other answer useful please mark the answer as correct or helpful.
