Enchantments ALWAYS Level 1

To put it simply, I have plenty of levels when I open the  enchanting table, but all three enchantment slots are level 1 each time. They are also mostly protection I, impaling I, and projectile protection (I have MANY already). I understand it’s rare to find something good, but I can’t seem to get anything useful like efficiency III or silk touch in my many hours of trying. Thanks!