I can imagine your stress. I'm the mother of twins. (they are now 16) but I remember when they were babies, and they kept crying and crying at the same time, I would just sit down and cry with them sometimes. As an adult that's stressful enough, so at your age I can just imagine what you go through.
The only advice I think I can give is this: Enjoy the time you have away from the house. When you're home, help out when you can (that doesn't mean be their full time mom) And possibly invest in some good earplugs
When you're helping out with them, see if you can come up with something new that could calm them. Maybe a certain music, or a certain way you talk to them. YOU could just end up being your mom's hero!