This is not your whole inventory. It is a tally of your items from the 1st of the current month to now. It resets at the start of every month. If you want to see your full inventory, click here or go to the inventory tab of your profile. If you make a negative or neutral amount (IE, you find 5 papyrus, then use 5 or more), then that will not show on the list. If you have not earned any items this month, then the page will appear empty!