Dude. It's better if you sow seeds every 1 or 2 weeks. The problem growing cilantro is they can bolt (flower) very easily under stress and hot weather. Once they flower, the plant will slowly die until the seeds mature (just like an Auto strain). Planting a few seeds at different intervals can ensure you get to harvest the leaves for a longer period. Just something to consider next time actually you can still do this.
When the it goes into flowering mode, they will grow finer, smaller leaves and develop a very strong taste (which may be too strong for some people).