M.G.
I would recommend getting a doctor to check you out and see i there is an underlying reason you are so tired. Eat healthy, drink lots of water, take vitamins, get physical movement as much as possible. You have to take time for yourself, for individual kid time, and for your significant other. I like to *spa* myself, I love to spend time giving myself a facial, soaking in the tub, etc -- generally after my kids go to sleep. I also like to go to places to get these services done (usual a school or someone very affordable), then the kids either go with a sitter or their father. I am not sire how old your kids are or if their father is involved or other family members, but you need to have time alone to destress, exercise, do yoga, go on dates. You should try and schedule dates, alone with your man and perhaps with the whole gang. Find something you really enjoy or would like to learn with other adults-- dance, pilates, book club, cooking class, scrapbooking, etc.
Hope you can make time for you!!! Relax and breath!