Eyes - I think it is absolutely normal to waver at certain points during the process. Not using when you have a 'strong' resolve is the easy part. It's the rough days like today that decide how the story is going to end.
I think the feeling that you are somehow 'weaker' today than yesterday is just a mind trick. You have told yourself that you may have used if you had them within immediate reach. However, you don't know that for sure. In that situation you may have flushed them instead. Or perhaps you would have come up with a more creative fate for the pills. Either way the pills aren't there and you didn't take them, period.
There were plenty of times that I told myself something along the lines of "well...if you are dealing with cravings this strong now it is just a matter of time before you fold. accept your fate now, which is to keep using forever. you were a fool to try to escape in the first place." On almost all of those rough days I did end up folding. I suppose I am a glutton for punishment or maybe part of me secretly likes withdrawal. On the rough days that I made it I just stopped worrying about being 'weak' / 'strong' or anything else. It seemed absolutely hopeless and futile to keep on going on those days, but I did it anyway. I think it is expected to have days where you have to keep going even when it seems completely pointless to do so.
You aren't defeated unless you use.