Pair my Apple Watch back to my iPhone
Your Apple Watch will only upload that data to the paired iPhone. Check whether the watch shows up in the "Watch" app on your iPhone. If it does, you may be able to get them talking again by going to the Bluetooth settings, tapping the "circle i" and connecting the watch again. If so, they will sync and all is well.

If not, retrieving your last 2 weeks of data is not possible since pairing with another phone will cause the loss of the data on the phone.