Please help-Hardened milk sacs.

Hi again.
I've only posted here a few times, and every time it's been for advice to do with a stray and/or her kittens.
I have another problem.
One of the kittens had a cuterebrae(I spelled that wrong, sorry). We took it to the vet today and all is well with him. We brought the babies inside two days ago(earlier than I would have like to separate them from mom, at 6 weeks). My mother will not allow the mom in, the kittens are weaned.
Just a few minutes ago I was outside petting mommy, when I noticed that all of her milk sacs are hard. I know that in dogs this is a sign of a major infection of the milk sacs. I can't remember the medical name for it, but I know it is deadly.
I really can't afford to take this cat to the vet. I just spent $120 on the kitten, and I couldn't afford that.
Is it possible that this is happening because she still had milk and wasn't feeding them, or is it likely to be an infection?
If anyone has any advice, I would really, really appreciate it.
Thanks in advance.
Lena.

hard milk sacs, hot to the touch seems to be in pain when touching are signs of mastitis. hard milk sacs could be the first signs of this. if you can not afford to take her to the vet and because she is a stray is there any no kill shelters around near you that could possible take her in? mastitis can/is deadly if not treated.
also she will either need to be spayed by you, if not then please get in touch with a no kill shelter as she will become pregnant again.

Mastitis?
She really needs to go in for a vet to check. Maybe they will work with you on the cost.

It could be happening because you took the kittens away from her two days ago,and she's become engorged with milk. She could dry up,or like the others have said...it could turn into mastitis. If you could have left them with her a while longer,or maybe just taken one at a time,it may have helped. You might could try letting one of the kittens nurse to help relieve her discomfort...but I'm not sure if that would help now. You can always try calling the vet,especially since you just had the kitten there. They may be able to give you something to help dry the milk up.