That is a tough situation, with the dad abandoning her. I have a young teenage boy, whose dad is not there for him for years now. It is hard, and makes you feel guilty for leaving them when all they have is you to depend on.

But, at the same time, unless we are healthy we aren't doing them any favours. If you do go out and socialize, you could always bring her along to the things you said she would enjoy as well. But you do need time for you. If it could be scheduled in since you are taking an online course right now, even an hour out for coffee with a friend, or to the library for a book club or something, or take a yoga class, spin class, something during the day that gets you out with other adults.

Being the only person with your child, without other adults, can make your depression much worse. I've learned that from pretty much isolating for most of the last 2 years. I am just getting out now and trying to make friends and have hobbies. I know it is easier for me as my son is older than your daughter, but he does have learning disabilities so I'm not too eager to leave him alone either. Your daughter will be okay with you having one night a week, or even just once a month. Get a babysitter or close friend to take over. It's very tough being a single mom.