My cat has a red runny eye

i dont know how to add pictures but im very worried for my cat. shes 2 years grey tabby that weighs about 5 pounds old and usually very hyper and mischievous. recently though she has been sort of mellow. she paws at her eye and it looks a little swollen. i dont know what to do. i cant afford a major vet bill right now. but i also dont want to wait until something horrible happens. my heart hurts thinking she might be in pain. my local vet doesnt open until monday and urgent care would be sooo expensive. im scared and i dont know what to do