Unless you've done something to your system lately, I'd agree with the suggestions that it's most likely a vent problem or (less likely, imo) your tank is full.
If pumping doesn't help, it would be best to have someone knowledgeable take a look. You might catch something early enough to avoid a system failure or more expensive repair. Right now the effluent is creating more suction in the system than it an draw through the vent. The gurgling symptom is air being drawn through the traps under the sinks.
If the trap is being drained you will notice a sewer smell. As an interim solution to the symptom you can install a relief valve near one of the sink drains or along one of their outflows.
From a horizontal line, add a Tee and a nipple 'up' with the valve on top of the nipple.
From a vertical, use a Tee, then a nipple to an elbow, then another nipple (up) to mount the valve on.
There are specialty valves for this purpose that include a dust filter. They cost about $50. If you can't find one quickly and don't want to wait for an order, for $10-20 you can use a one-way water valve that will work just as well. Put piece of nylon stocking over the end as a dust shield. Home Depot and Lowe's will have the water valves but not always the specialty valve.
Remember to tell the plumber about the temp fix so it will be blocked when they do a system test!
Once the system is back to normal, you can remove the valve and cap the addition or (if you got the water valve) just screw a cap over the end of it.
In case you're wonderring... I am not a plumber but I do a lot of my own repairs and upgrades. I recently added a 'laundry-pump' after my laundry sump failed (
http://www.winnipesaukee.com/forums/...ead.php?t=5535 ). My gray water drains all flow into a 'main drain stack' that merged into the septic line. The vent runs into the septic line. This allowed me to be comfortably certain it was not a vent failure. The laundry output was drawing water out of my tub and I got the smell. I could have just kept running water into the tub after a load of laundry but I really don't care for that odor!
That's pretty much all I know about that but PM me if you want to bounce some ideas around.
Good luck!