First of all, you are doing really well for going 18 days hardcore. It is not that easy.
However, realize that even if you don't watch anything. Triggers could be everywhere. In particular, negative emotions and boredom are the common ones. Even if you don't encounter any of them, urges can also pop up without any reason (due to old mental habit). Therefore, it is important to get yourself prepared right before the urges hit.
The first thing you may want to do is to build up a system to tackle with your urges. This is never easy, and it requires some practice (I am not doing well, but I believe practicing would help me to improve). We need to make it a habit to redirect the focus when urges come. It is very common for us wanting to fight our urges, trying to stop them or so, but by focusing on them, they often grow in power (i.e. more strong urges). The best way to do it is to ignore them, not to follow them, and focus on something else. Some people may focus on a "motto" (some "magical words"), or what to do when they are bored / feeling down. By focusing on something else, the urges will come and go naturally. Alternatively, you may also want to try observing the urges in the third person (just stare at them without commenting), and detach from them.
Don't lose hope, it will be worth it. Good luck!