@Zohaib , it sounds as though your bird may have been injured or may be in shock. You did the right thing by separating the birds. You may have to separate the remaining birds -- male peas can become very aggressive towards each other during breeding season.
Keep the ill bird where it is safe. Check it for injuries if you can -- examine head (and eyes!), wings, legs, body. It may just need a few days to recover. It needs to stay warm -- but not too hot. Make sure it is not shivering -- the AC may add to the shock if it is too cold.
Make sure it has plenty of water. If you can weigh the bird, do so right away so you can tell whether it is losing weight and how much medicine and fluids to give it.
If the bird becomes dehydrated, you may need to give it fluids, either directly in the throat, in the crop, or under the skin. @casportpony can help you learn how to do the crop and skin rehydration. If you give anything in the throat, BE SURE to get it in the correct place -- NEVER THE CENTER!!! That's where the bird breathes -- it has a separate tube on the side that leads to the crop.
Can you get pedialyte in Pakistan? There is probably something similar, perhaps @q8peafowl can help explain/identify local equivalents. What you are looking for is an electrolyte replenishing fluid -- pedialyte is one that we give to infants and small children when they become deyhdrated, instead of plain water. You should be able to find something like that in a local pharmacy.
Keep us posted, and send photos if you can. Hoping for a speedy recover.
GP