If i went swimming in a lake with a perforated eardrum without earplugs should i be worried?

Probably yes.: You basically laid out all you need for a serious inner ear infection. 1) Lake water teeming with organisms. 2) Outer ear canal easily fills with water and does not empty. 3) You have a hole into the deepest part of your skull. This is not to scare you unnecessarily, but you DEFINITELY need to see a physician if you have even the SLIGHTEST symptoms.