States of permissibility or rulings in (Sunni) Islam fall under 5 categories (7 for Hanafis). One of those states is haram (impermissible) and the rest are at varying levels of permissibility (halal):

1. Obligatory (fard or wajib)
2. Recommended (mandub or mustahabb)
3. Neither recommended nor disliked (mubah)
4. Disliked (makruh)

All the above categories are "halal."

To answer your question, yes, if it is not halal then it must be haram. There is no "in-between."

States of permissibility or rulings in (Sunni) Islam fall under 5 categories (7 for Hanafis). One of those states is haram (impermissible) and the rest are at varying levels of permissibility (halal):

1. Obligatory (fard or wajib)
2. Recommended (mandub or mustahabb)
3. Neither recommended nor disliked (mubah)
4. Disliked (makruh)

All the above categories are "halal."

To answer your question, yes, if it is not halal then it must be haram. There is no "in-between." Imam an-Nawawi's hadith about doubtful matters refers to things about whose ruling we are unsure of (due to a lack of a clear cut text about them or for some other reason); it does not mean that there is a separate category "doubtful" that they fall under.