My cat’s treatment

My cat is always sick for every 2 weeks now. The vet says it's because of stress a month ago. Now, he's not eating for 2 days now because of gingivitis. It's so sad to see my cat can't eat properly and he already lost weight from not eating. I want to take him to the vet and get him treated but I don't have any money right now and because of pandemic, I don't have that much on me right now.

Any amount will do. I want to save my cat because he's been with me for 3 years now and he's too young to suffer from these.