My Site is new only been live around 2 months. When i bought the domain it all ready had one backlink and my domain authority from just that one was 21, however yesterday that link seemed to have been removed and by domain authority has dropped to 1. It does not make any sense that one domain can impact so much. Despite this I have been working hard to add many more links but none of these have appeared and some are from major authority websites.  My domain is https://www.stampit.co.uk/

Can you kindly shed some light on this. Many Thanks