I talked with my OB/Gyn about something similar to this. I said I felt "stuck in Mom mode". It's hard to feel sexy when you have spit up on you or you spend the whole day being needed for something/someone, etc. It's just that I'm so exhausted by the end of the day.
No, there's nothing medically wrong with me, it's called EXHAUSTION. She said I needed to ask for help, from my mom, get a sitter, cleaning lady, whatever it takes to get a break from the kids and housework.
Also, she said I NEED to plan date nights and Girls Nights Out. I said, "Are you kidding?!? I'm already exhausted and a SAHM (limited budget being on one income).
She said she hears this several times a WEEK from moms coming in saying they have no drive anymore. She said it's because we are always GIVING GIVING GIVING until we're spent.
I have felt a little better since trying to take her advice. It really does wonders to be alone, get lunch with a friend, etc.
I bet if you took some time for yourself, to find yourself again instead of being "Mom", "wife", "coworker", "cooker", "cleaner", etc. you'd be happier and WANT to have sex. It takes time. Think of it as an investment in yourself and your marriage.
Hang in there! And do talk with your dr to rule out any medical issues for yourself. You are not alone!!!