pregnant an onlt getting 3hours of sleep

Hughes • mommy of 4

i have a 1year old an 9month old an currently pregnant im so tired that im falling asleep while watching them play during the day but my 9month old is only sleeping 3hours a night an he only gets 1nap a day an its for 2hours but i cant sleep shen he sleeps since i have a 1year old who dont nap an i have no one to watch them so I can sleep im in need of some help or ideas to get this boy to sleep at night i dont think i can do this one more night.