Could i have broken a sewer line while digging my garden?

I live in a duplex and was digging by the side of my house today about 8 inches deep. i noticed by the side of the house was a concrete slab jutting out about four inches from the side of the house. I kept digging in front of it, and for a minute i thought i smelled something nasty. Later on my neighbor was standing in front of my yard and remarked " Something smells like dookie out here". Am i just being paranoid or is it possible i busted a sewer line or something equally as bad? I dug without my landlords consent, so now i'm really worried i've done something terrrible and expensive to fix, not to mention i had my bare hands in poo. possibly. please please help!