I would say try to increase your daytime/nighttime temperature if possible and try to allow your soil to dry out a bit more than usual before watering it again. Since your night time temperatures are in the low 60's root growth slows down or almost stops. Also try warming your water up a bit into the 70's watering with cold water further cold shocks the root system. You can also try to use a seedling heat mat under your pot to try to warm up the root zone.