Severely drooping peace lily
I have a very sad peace lily. I have had it for a few months and it has always been slightly droopy. I water once a week. It never perked up too much after watering, but it did grow new leaves and a flower. I rotate it once a week as well because the leaves closer to the sun wilted less. I have moisture gnats. For the last 2 waterings, I added dish soap (1T) and vinegar (1t). Still gnats. A few days ago, I sprayed with an insecticide supposedly safe for indoor plants. A day or two later, the flower completely drooped. Now the leaves are as well. I moved it to morning sun, but do not know what else to do. The leaves are a vibrant green but the edges are yellowing and browning slightly. What to do? Is my pot too big? Did I kill it with chemicals?