From the pics it looks like you are severely overwatering and it appears that the stem may be rotting. Let the medium dry out, do not add water again until it is dry. If you stick your finger in and feel moisture, hold off. Also, pay attention to the weight of the container, that's how I typically judge when to water. Light pot needs water, heavy pot is wet. Takes a time or 2 to tell the difference, but it's pretty reliable.

We would need a little more info to delve any deeper into other issues you may have, I just wanted to suggest that because if you continue you will starve the plant of oxygen and potentially kill it.

Look in the plant problems section for the troubleshooting form and cut and paste your answers here. I'm sure some people will be willing to help out.