iPhone splitting phone numbers from contacts?

Hello! Over the weekend, my phone decided that everyone’s number that I have had saved wasn’t the case. Does anybody know what happened/how it happened? For example if the number was (123)456-7890 then a text would come in from a “new number” like this 1234567890

Then, if someone were to reply to me it would include me as a contact as well. So it would be me and my iPhone self contact. It seemed to only impact the people I have in my phone that don’t use iPhone