@reallyreallynotok
(((HUGS)))
what a horrible way to feel, I'm sorry you're feeling like that xx
what's your relationship like with your teenager?
is your toddler one to snuggle or prefers to be off doing their own thing?
are you going out working tomorrow or home with the toddler?
can you text with a family member or a friend if actually talking feels like too much? I bet there's at least one of them that would love to have the toddler for a day over the weekend, or come & stay with you.
as others have said, try to book a GP appointment & get checked out. being low in certain things can make you feel very low.
What's your work situation?
how are the finances?
why do you feel you're letting your kids down? I very much doubt you are, but why do you think you are??
take the youngest (in a rain suit if necessary), for a walk/to the park, they'll love the novelty of it (assuming you don't usually go at this time of night) & the fresh air will do you good.
if by some miracle they're already bathed & ready for bed, make yourself a cup of tea & go and stand in the doorway breathing in the fresh air.
have cuddles while reading stories, doing bed time routine, then find some easy watching on TV. Give your head a break!
but loads of us here if you want to talk xx