Whew, I sure do understand your predicament very well!
I am divorced as well, with 2 children. We split custody 51/49, but he gets them during the weekdays & I get them every weekend. It is a very hard "pill" to swallow. I frequently put myself down for not being the mother that I should be ~ the type that my girls deserve. Thoughts like this don't help me feel any better though & often lead me to self-kicking and intensify my self-hate. I'm trying to change that dark tendency of mine...but it's not an overnight process.
Fact: I am doing the best that I can. Giving the most that I can. Trying to be healthy enough to make my girls feel safe, loved, and able to talk with me about anything (anytime). That's the best that I can do right now. I keep hoping that my condition will continue to improve as I continue my best to try...but I know, it takes time. I wasn't made to be this way overnight & I therefore shouldn't expect to get better overnight either.