My thoughts are when a job causes so much stress, that maybe it is time to search for another one. Since the "older ladies" seem to be causing you anxiety and not being friendly, is maybe a sign you "may not fit in" and they are trying to push you to quit or perhaps they are taking their stress out on you and causing you to be miserable...... Either way, perhaps another job would be better for you...

or

You can talk to the manager.. Be frank... Let the manager know what is happening. And if things don't change, I would start putting applications in for other jobs...

Besides those cranky, pushy, negative "older ladies" don't sound like a whole lot of fun to be around..