Laura,
I hope you find a church with a strong support network for single parents. At my old church, half or more of the congregation consists of those who are raising children alone or are now in blended families, so there was a lot of understanding and they always tried their best to provide childcare at their events.
I know this is a bit different but I can certainly empathize. I dated a guy for three years and because he was an alcoholic (to an extent I didn't understand at the time), I pretty much became the single parent of his two boys, ages 18 mo. and 4 at the time. Their mother had passed away almost a year before I was in the picture, and their father, once he became comfortable (and saw that the kids and I had attachments to each other), quit his job to drink full-time, leaving me to care for his children. I had to make sure they were bathed, dressed, and fed, because otherwise it simply did not get done. Next to my divorce, it was probably the most stressful period of my life.
I took the boys to church with me by myself. The relationship was horrible, but the best thing that came out of it was what I learned from his kids.
I will never forget his older son asking me, "Kim, why does God love us?" and I stammered around for an answer...
I'll always be grateful for everything his kids brought to my life.
Best wishes to you and I hope you find some support for your unique challenges.