I dropped a friend

I sort of knew this woman in school, and we reconnected years after. She is a not a bad person, but things about her dragged me down and I ended the friendship, but now I feel guilty that i didn't handle it well, even though I do not want her in my life. She has severe financial problems from credit card debt, she is over medicated for some kind of disorder and has a very "flat" affect-doesn't show much enthusiasm, never goes anywhere, and I don't think has many other friends. She asked some large favors of me and I did them for her. She does not have much to say, her house is filthy and she didn't bother to clean it even a bit when I went over to her place in the past (dirty bathroom, cat litter next to kitchen stove)--her dog got poop all over my car once and she wouldn't have done anything about it if I hadn't said anything…I know she is depressed but she is not what I want in a friend. I can handle people's ups and downs and we all have them but this was too much. I didn't want to tell her directly that I didn't want to be friends. I felt that would be too direct. Instead I said I was busy. She then called every week wanting to get together. She became more insistent and kept calling me. I always said I was busy--as I was. Getting together always meant a half hour drive for me because she is afraid to drive distances, so we would meet and she would have little to say….finally I just blocked her calls. There is no easy way to end a friendship. I didn't want to hurt her by telling her the unvarnished truth. maybe there was something in the middle that I could have said but I was afraid the conversation might have escalated.