Hi Ruith: Don't fret...Oak masting is very cyclical and varies from year to year: no acorns, few acorns, some acorns, many acorns, and acorn bumper crops!
It is also important to note that some oak trees are simply poor producers of acorns, whereas other oak trees are consistently good producers of acorns -- this is likely influenced by genetics.
Tree age is another factor worth mentioning as mast production drops precipitously as trees reach senescence or maximum biological age for their species and environment.
Weather also plays a significant role as wet, cool spring weather can significantly affect pollination and thus acorn production.