As hughmac4 suggested, given the lack of track, this sounds like the GPS is off and distance is coming from stride (either directly from the watch or a footpod/sensor if using one). If the case, then the question becomes has the GPS been turned off accidently in settings or is it broken?
-Check the settings for the applicable activity you are using (assuming it is not 'treadmill' by accident) and the GPS configuration is correct.
-If you are using a sensor that can also measure stride then make sure it is not set to always provide distance.
-You'll need to google it but there will be a way to get the 245 into diagnostic mode which will show if there is an issue with the GPS chip. EDIT: Found this that has the steps on the 245 to enter diagnostic mode (and get out of it:
https://forums.garmin.com/sports-fitness/running-m... -Hard Reset - hold the light button down for 20 or so seconds to shut the watch off. Then restart. Note that this does NOT remove any data.
Full reset through the system menu - last resort as this does remove all data. Garmin support will likely default to this anyway!