It sounds like she's weak from an infection in her uterus or maybe in the milk ducts from nursing. She really needs to be seen by a vet and probably needs antibiotics. From what I've read about those infections, they can be very serious.
If you don't feel like making any recipes, another option is to get a kitten formula milk replacement. What we have in the US is a brand called KMR, I don't know if they carry that in India or not? I'm sure they carry some kind of milk replacer there-maybe not this brand, but maybe another!
Good luck-please give us an update!
She may be very weak, and it could be related to her diet. What are you feeding her? Lactating cats should be given a diet rich in protein, fat, vitamin A, E or Multivimatin supplements. You may want to either get a commercial food specifically for lactating cats, or prepare her own meals. Here is a good recipe I found for you:
Ingredients:
8 cups water
2 cups polenta (if cooked about 8 cups)
4 eggs
4 tablespoons olive oil
1 ½ kilos turkey or chicken, ground
8 tablespoons Cat Multi Vitamin Supplement, powder
4 tablespoons bonemeal or 1 ½ teaspoons eggshell powder
20,000IU Vitamin A
200-400IU Vitamin E
2 teaspoons fresh greens with each meal (optional)
1000 milligrams Taurine supplement (optional)
Healthy Hints:
Feed your pregnant or lactating queen approximately this amount daily: for small cats: ½ to ¾; for medium cats: ¾ to 1 or more; for large cats: 1 ½ to 2.
It is a good idea to use both white meats and red meats, or combine both at the same time to ensure plenty of iron and other nutrients.
If you use red meat instead of white meat it is better to use slightly fatty meat. If you do simply remove the olive oil from the ingredients.
If you do not have polenta available you can use rolled oats (same proportions) or 8 cups of mashed potatoes.
It is also possible to use 2 cups (dry) of any of the following: barley, brown rice, couscous, amaranth, bulgur, millet, buckwheat, spelt or quinoa.
Polenta, which is more coarsely ground, gives the best texture. You can usually find it in health food stores.
Add extra yeast for more nutrition and flavor.
This dish is not only excellent for pregnant or nursing queens but also for their young developing kittens.
If she doesn't improve, take her to the vet. It might be nutrition related but it might also be something else. IMHO, I think you should talk to the vet, and I would take her ASAP, but I'm paranoid like that lol...
Is she feeding the kittens?
Good Luck. Let us know how it goes.