Hey there so over watering can cause this droop effect, but being in only 1 gallon pots and your plants arent just little seedling, they're nice looking young veg plants. Under watering can cause this similar symptom, hows your fans? Do you have some that are going all day or most of the day? The majority of your photos seems pretty dry soil, not muddy or extremely dark with water. Watering once a week doesn't sound excessive to me. When you do water, do the plants perk up or do they stay the same? If they perk upwards then they're under watered, if not then look into extending you waterings a few days more than a week, or up your air flow around the top and bottom of your grow space. You could also try a mild feeding of kelp extract as this is a common "plant tonic ".
Happy growing friend, I'm sure they'll battle through since their over all health doesn't seem too severely bad as of yet.
