We have a cottage - and we are newbies! 1st 2 years no issues with plumbing. This Spring the toilet is not draining properly and the shower and sink drains gurgle when we flush the toilet.

My guess is your vent stack has become clogged over the winter. Leaves,debris and even small animals can plug it up. Rod from the roof with enough snake to reach roof top to basement plus 20'

With a similar situation I finally found that where the fluids drop into the septic tank some roots were partially covering the pipe causing a backup with slow flow.

Gurgle says something else to plumbers.

Gurgle says something else to plumbers.

$$$ for a getaway WE? ;-)