I can see this dude posing in the mirror saying, "I'm ridiculously good-looking."

Dear Prudence,
My girlfriend and I have been seeing each other for four months. When we started dating she told me she usually doesn't go for guys as physically attractive as me, which I found odd. She is very cute but not the hottest girl I've dated. Her intelligence, personality, and character are why I've fallen for her. Things have been great until the last two weeks when she started becoming more distant and less affectionate toward me. Last weekend she went with her single girlfriends to the Caribbean for a brief vacation. I barely heard from her the week after she got back, but we both have demanding jobs. I ordered flowers to be delivered to her office. She then called me and said she no longer wants to be in a relationship, and that I’m way more attractive then her previous partners. I asked had I done anything wrong and she replied I've been perfect. But she said while on vacation she barely missed me. She said she fears if we continue, I'll find someone better looking, or worse cheat on her like her last boyfriend. I asked her to reconsider since a weekend of no communication is too short a time to make such a huge decision and she agreed. I feel like I am being dumped based on my looks. I don't want to lose her but I wonder if it’s worth it to get back together if she reconsiders. Do her girlfriends have something do with this? What should I do?