Whatever you do DO NOT seek "professional" help! All they will do is put you on pills that won't help anything. Depression is situational, not a medical problem. You have it right, only you can fix this... So the game is half won already.
I don't know what your religious beliefs are, but talking to my priest always makes me feel better. God will only help if you want Him to. I think you'll be Ok...You already took the first step. Remember, when you're stuck in a spiral of shit...it's time to start swimming. Your kids don't expect you to be perfect, they just expect you to be there. Hug them, tell them you love them. Sometimes you have to fake it till you make it!