Hi
For future reference, it is not necessary to unpair and re-pair Apple Watch when it becomes disconnected. If your watch becomes disconnected via Bluetooth and cannot connect to a known Wi-Fi network at the time, it will show the Disconnected icon on the watch face:

Bluetooth disconnections occur whenever the paired iPhone is unavailable (such as during iOS updates or when your iPhone is out of range). Your watch and iPhone should reconnect automatically a short while after being brought close together again.
If they do not reconnect automatically, rather than unpairing your watch, instead try keeping your iPhone and Apple Watch close by each other and following these steps until they do reconnect:
For the best performance from your watch, keep both Bluetooth and Wi-Fi permanently enabled on your iPhone.