Can I reactivate my original number

Contact your carrier if you have accidentally erased your eSIM too.

Reset of Network Settings will not impact your eSIM.

Even when you do complete erase the iPhone will offer you to keep the eSIM see the pic below

Erase --> Erase iPhone - Apple Support (IN)

1. Keep eSIM Data was the option I chose (See the pic)
2. .

To activate iMessage and FaceTime using your Phone number

1. First, check to know whether you have an SMS plan enabled for at least One SMS*** with your carrier. Contact your Carrier (Cellular Service Provider) the agency that issued the SIM to you
2. If your iPhone is used with a carrier not found in the wireless carrier articles, make sure you can send and receive international SMS. (One international SMS*** Only)
3. If you can't turn on or sign in to iMessage or FaceTime - Apple ...

*** You may not have an SMS plan (Domestic & International) enabled by your carrier for the SIM/eSIM that you use on your device. Apple Inc does not provide SMS services.

So, I reset my phone, and it won't let me get my phone number back and I am on my email but I do not want to use my email I want to use my phone number.