Your liver is plugged. The kidneys have to pick up the load. Dark urine. You'll also get some nasty skunky body odor. All signs you need to flush.
Look, get on Barefoots DeWormer and after one week on that start decongesting your liver. I don't care which flush you use but get going on it. You'll be glad you did.
The fear of it is because it's an unknown. You'll fear anything unknown.