I used to have a friend who was exactly like that. At first, I thought it was great because she always wanted to hang out. She would come up to work (we both worked at a convenience store together) and hang out, help me close, etc, etc. But then, she wanted me to do the same thing. I am married, and live at home with my husband. She couldn't understand that although I wanted to hang out with her, I had more responsibilities that I needed to take care of. Then, when I got home, she would call me & want to talk on the phone FOREVER!
So...I found another job & stopped answering the phone. Probably not the best way to handle the situation, but she was emotionally draining to be around. I couldn't handle it anymore. Being with her was physically exhausting.
Anyways, I know what you are going through, & I wish you the best of luck in whatever you decide to do to fix the problem.
Sam