Could you try to address the reason as to why you're so tired rather than trying to find a "quick fix"
I can totally understand having 2 little ones would be so tiring, is ther any way your DH can help out while you have a nap to recharge the batteries every so often etc?
Sorry if you've already thought of these things and they're not working, I'm just trying to find ways to help, sleep deprivation is no fun at all!
Big hugs to you
xxx