Looks like a two fold problem, biggest has already been stated the light is either too far away or not enough light since they are stretched. The other part appears from the photo that they are not getting enough wind to encourage the stem to thicken. you might want to prop them upright and make sure that they have a little breeze on them, at this point not much just enough to make them strengthen their stem. The problem is usually corrected in a day or two. One other thing you might want to give them a weak solution of molasses in their water next watering, like a teaspoon per gallon of water, this will give them some extra sugars which will help them bulk up a bit quicker. Hope this helps and good luck.