I've come across all sorts of women in my life, I'm not 30 yet but close to it, I personally have never come across a girl to leave for my size.
But trust me if she's ditching you for D-size she's not worth it.
There are a lot of women out there the planet has 7+Billion people on it, one person isn't worth killing yourself over, take sometime to yourself and enjoy it.
Last of Us 2 is about to come out buy that game and waste hours playing it
If your not a gamer find a workout plan buff yourself up and become a beast
Don't like the two above find something you've always wanted to study and purse it.
There are plenty of hobbies you can do to keep your mind busy.