Sick outdoor kitten with goopy eyes and not eating. What should I do?

Hi there and thank you for using Petco Pet Education Center, formerly Petcoach to address your concern. It appears as though Wraith may have a respiratory infection and the thin body condition could be due to failure for her to thrive from the infection. She may also have intestinal parasites that could be causing the poor weight gain. I would definitely consider bringing her inside and keeping her in there out of the cold weather, especially considering she is so young and thin. If you are concerned about cost at a vet clinic, there are plenty of rescues you could reach out to to see if either they have any medications to donate or if they could take her from you so that she can get the most appropriate veterinary care. The only other option you have is to make sure she is eating enough and can even add kitten formula with the food and wait for her immune system to fight off the respiratory infection. However, there may be more going on. If you cannot afford to take her to a vet clinic, then my recommendation would be to give her up to a rescue so that she can receive the care that she needs. I hope this helps! Please let me know if you have any other questions / concerns.