Dont really know what i can do about this situation and worried about my pony?

you may need to call an animal control service to remove the bodies. it sounds like it has become a safety and health issue, not just for your horse but for you. i wouldn't be worried about your horse if she is grumpy. the sheep have become a serious problem so focus on getting them removed. you don't know if the sheep have been well cared for health wise or what killed them. this is a serious problem that needs to be dealt with immediately.