I've had these "tonsil stones" off and on for the past 20 years. I am prone to tonsil infections, and have had a doctor recommend removal of my tonsils. I'm trying to avoid the surgery, but we'll see.
Generally, not a big deal. Good oral hygiene is a must. I also try to gargle with salt water because that helps to keep bacteria at bay.
You could try an internet search for "tonsil stones" -- many websites give suggestions on how to handle these.
They are called tonsoliths or tonsil stones...VERY common.
There are irrigation systems out there for this (forget the name)and you will have to perform a google search if interested.
Not much to worry about unless they cause frequent infection. Practice good oral hygiene.
I have the exact same thing and a doctor also told me it was extrudate. But I noticed it turned up after eating certain foods (chips for example). I haven't had it lately. It can be both things I reckon.