My toilet’s water level is low. The toilet was flushed and the water level rose to the brim and then slowly drained until the water was so low that it bubbled. The toilet water remains low. Then when used again it did the same thing but did not flush the poo. Flushed again awhile later the tank filled up and stayed at that level for about a minute and then started slowly draining to a loew level.
your drain is blocked…some where down stream of the toilet, find an inspection, or access point to the drain, to see where the blockage is. you can try unblocking yourself, however if it is a hard block, like tree roots etc, you’ll need a plumber to come out with a drain cleaning machine.