There can be many reasons, however, since you mentioned "many days" you'll need to understand 2 things.
1. It's mainly something to do with your
liver/ gall bladder functions.
2. Get your stool examined and consult your local GP, it's not really worth ignoring or waiting.
Next Steps
Your GP may ask you to get a
Liver function test or other tests to see if your liver and gallbladder are functioning normally and there are no gall bladder stones.
Health Tips
This looks like a 100% treatable problem, just get in touch with your local GP or may be with me, and you'll be guided further accordingly. Take care and get well soon!