Live on septic tank, downstairs toilet started bubbling and now is constantly overflowing

Is the septic tank full : have you checked it ?

Have you checked to see if it is merely a clogged drain ?

Have not checked septic tank -- Today, while having Easter, noticed downstairs toilet bubbling -- when checked, toilet was almost overflowing, husband used a plunger and water slowly, but eventually went down. -- A few hours later downstairs toilet was used and flushed as if nothing was wrong -- Tonight, husband took shower upstairs, and downstairs toilet flooded and leaked all throughout the foyer to the front door.

Read on internet check septic "cleanout pipe", but my husband and myself have no clue where to even begin to locate this -- any other suggestions?

Have not checked septic tank -- Today, while having Easter, noticed downstairs toilet bubbling -- when checked, toilet was almost overflowing, husband used a plunger and water slowly, but eventually went down. -- A few hours later downstairs toilet was used and flushed as if nothing was wrong -- Tonight, husband took shower upstairs, and downstairs toilet flooded and leaked all throughout the foyer to the front door.

Read on internet check septic "cleanout pipe", but my husband and myself have no clue where to even begin to locate this -- any other suggestions?

There will be a pipe like a sewer pipe that runs from the home to the septic tank.
Do you know where your tank is in the yard ?
But between the house and tank there is normally a clean out for the sewer line. At the septic tank there is often another pipe going into the tank.

*** not all systems have them.

When was the last time the septic tank was cleaned out

It could be a septic tank or field issue but 9 out 10 times its something else so lets check that first. There should be a main clean out cap about 18" inside the lowest level or just outside. Let us know if you found it

My husband has lived here for about 7 years, he said the last time it was cleaned out was about 3 or 4 years ago.

18" inside the lowest level? The only thing we can locate is the cap to the septic tank outside in the back yard. Would the main clean out cap be near this?

That would NOT be the clean out for the main drain line but is a clean out if you were to get your tanked pumped out. The clean out is on the lowest level of your home right where the drain exits the foundation, 18" inside or outside. If its outside it may now be covered with dirtand/or bushes.

Also if you know where your fields lines are outside, check and see how dry the ground is. Does the ground above the field lines remain soggy most of the time? If so,it might be that your water is not draining off fast enough.