Dirty panties

I have a question. Why are my panties yellow dirty, especially when i wear them, but i cannot even clean it after washing it. What is it? Is it after discharge? Girls pls tell me if you also have panties like this or should i see the doctor? I think my discharge isn’t yellow but i don’t know. I wipe myself well i think. Please because I am worried that this is something I should be ashamed for and idk if it’s normal :(

It’s more yellow in real than in the photo but i think you can see this