Advice please- post abortion!

I had a medical abortion about a month ago, I passed lots of clots and tissues and believe that the pregnancy is over. 
However, recently I've been having foul smelling brown discharge appear- also today when I went to the toilet I saw that there was a solid lump of brown stuff that was solid and looked like a tissue of some sort. 
I'm really worried and feel really unclean and disgusting please can someone tell me what this is? I've googled but don't know how to word it.