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What you are seeing is a little conjunctivitis. There are two causes. One is that it's bacterial and you might need antibiotics. The other reason could be that she has injured herself somehow. You can wash the eye with some warm saline and a gently clean it with a towel. If it doesn't clear up in 48 hours, you need to see the vet.
The other concern that you have is about the mucus. Cats have glands at their rear end called anal glands. Every time that the cat poops, a small amount of this substance is secreted. It's goopy and smells bad. If it continues, you can see the vet to have the glands expressed. Until then, use a baby wipe to remove the goop and the smell. Aside from that, mucus is present in the intestinal tract and presents when the cat has a tummy ache. If this persists as well, a vet visit may be needed to determine the cause.
Let me know if you have more questions.