toddlers are ridiculously difficult

I think, as in RL, it's all a matter of being organized. Work on the toddler's skills, the thinking one in particular, as this will help them to throw fewer tantrums. I often have two or more toddlers in a family at the same time (not twins or triplets, either, just varying ages). I do use the MCCC mod which I use to help the teens/YAs and Adult Sims ahead of the game needs-wise, so that they don't starve to death or suffer humiliation by peeing their pants whilst attending their little toddler darlings.

Take a deep breath :) (and let it out slowly) and view this life stage as the challenge it is. It's a challenge in RL, too. But so worth it in the end. ;) And I'm here if you need to vent.