Have you thought about you might be under watering them? I have had my plants do just about the same thing when under watered. They were droopy even after I watered them. I started watering them every other to third day and she recovered. I'm not for sure this is the case with your plants but that sounds like what mine was doing when I under watered her.
Small pots dry out to quickly and after rereading your post, you are probaly root bound and this is causing your plants to have a double wammy effect on them. Small pots equals not enough water and root bound.