"I'm not sure I can handle two babies on my own, unlike my sis who is super-mom," Hart, 32, who gave birth to son Braydon Hart Wilkerson in March, writes on her MySpace Celebrity blog.
The actress and husband Mark Wilkerson, 30, a Grammy-nominated musician, also have 2-year-old son Mason.
"We are adjusting nicely to being a family of four, although it is a tough job," says Hart. "It's about to get a lot tougher as Mark leaves on tour this week."
But the actress says she, too, will be on a tour of sorts when she travels to New York to promote Pull-ups Training Pants and then to Baton Rouge to shoot a feature film in June, a thriller called 9 Dead that her mother is producing. And after that: she'll shoot a new ABC family movie she's producing.
But, for now, Hart is bracing for temporary single motherhood.
"Wish us luck on our travels," she writes, "and say a prayer for Mark that he doesn't die from heartbreak from missing his boys too much!"