I have a toilet, shower, and small sink all linked together for the waste pipe in a spare bathroom. Recently, the toilet clogged after taking a #2 and when plunging the toilet, water and waste would come up the shower drain and gurgle in the sink. If I try to flush the toilet to see if the clog has been taken care of the water raises as if the clog has not been cleared. Now after 30 minutes or so the toilet will flush as normal. I did snake the pipe and was able to get to about 30' before I ran into some paper, thinking this was the issue, I ran a hose at the entrance of the drain pipe and ran it for several minutes and nothing clogged up. Thinking this solved the issue, we used the restroom again for a #2 and the same issue happened (clogged up). All the same issues arose as before. One thing I did notice is there is no vent pipe in the bathroom (short of a mechanical pipe under the sink). Could this be the issue or is there something down the drain pipe past the 30' that I went (we have a septic tank)?