Why are my pumpkin seedlings drooping?

These seeds have been planted for about 2 weeks. The leaves aren't yellow or dead yet and they aren't drooping. Only the stems of the plants. They were growing fine until a couple days ago when they toppled over. I always place them by windows and place a lamp over them and water them around noon everyday. I just started putting them outside so they can adapt so I can plant them outside. I contemplated Dampening Off disease but the only matchng symptom is the drooping. It may have something to due with the fact that these gnats in my house are always near my seedling, crawling in the pots. I tried to get rid of them but.... Anyway this is my first year gardening and so far it's just hard and annoying. Can someone tell me what may be going on and how to cure it??? Thanks