Hi Frans,
Welcome to the site!

Sorry you have to be here but you'll find a lot of support and great advice here.
Congratulations for getting through the surgery successfully and don't worry about the discharge. It IS still normal as the wound heals, as long as it's not itchy or smells bad, which could indicate infection. If you read a lot of the other fistula posts, you will find others in the same situation and from what I've read it can take up to 10 months in some cases for the discharge to stop but it's still normal even at that stage. It does stop and really depends on the state of the fistula, size, position etc. and the surgery performed on it.
Sure this is perfectly normal, just keep everything really clean and you'll get there! All the very best in your healing :)