I would not recommend taking any of these meds without your doctors advice and certainly do NOT take the two together.
Sounds like you are overtired. When we are overtired, it is very hard to relax and wind down to be able to drop off.
Have you tried some relaxation techniques or taking a warm bath to help you relax. Drinking warm milk (if you like that sort of thing) or drinking chocolate and there are other night time drinks, can help you calm down to sleep too.
When your toddlers have a nap in the day time, have a lie down with them and a take a nap too.
If there is a toddler group near you, it may be worth your while to put the toddlers there for a few hours or get a member of the family or a trusted friend to look after the toddlers for you to get some "me time", relaxation and rest.
Make an appointment to see your doctor and discuss this with him as there may be another reason for feeling so tired and not being able to sleep.
Best wishes.
I would ask your pharmacist, I do not think I would try to take both however.