Welcome to Healing Well.
I am sorry that you are in such a bad spot right now, but I have to agree with gettingby, sometimes you just have to let someone go and move on.
IMHO she is using you for a conveince when she needs someone to take care of her. You need to set boundaries, IMHO, and stick to them. There must be someone else she can call on if she needs favors.
Please follow up with your Pdoc and continue your medication. The AD meds will take up to 4-6 weeks to kick in. Therapy to help you work on your self esteem would be something you may need to move forward.
Please take care of you and keep on posting here. There are many caring people here.