My toilet is clogged! When I plunge it this happens. What is it?

Septic backed up? I dunno,but my toilet was clogged up(still is) and I took a plunger to it. When I went to plunge every time I pushed/plunged down in the toilet ,water was being forced out from my sink and bath tub drain. Also,this will sound NASTY but pieces of you know what,not sure if it was CRAP..lol...but... show more Septic backed up? I dunno,but my toilet was clogged up(still is) and I took a plunger to it. When I went to plunge every time I pushed/plunged down in the toilet ,water was being forced out from my sink and bath tub drain. Also,this will sound NASTY but pieces of you know what,not sure if it was CRAP..lol...but what ever was coming through the drains everytime I plunged was black. Its truley a NASTY situation! Our house is only 4 years old,so not sure if its the septic.
Any answers on this would be GREAT. Im getting a plumber out here this week but would like to know a little bit of whats going on so I dont look that stupid when he comes.
THANKS!
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