Becoming very self-conscious. Self-esteem taken a nose dive. How to deal with that?

I've always been a quite confident guy.

That has changed since my scrotum has started to get larger/swell up a bit over a year ago. It has now grown to the size of a medium watermelon, not something I can hide anymore. Whenever I'm out in public people stare, some point and laugh. Can't really blame them but it's making me feel very self-conscious and hurt my self esteem. I've started to avoid going out as much as possible. Even hanging out with friends is something I've started to do less.

But what really made my self-confidence take a nose dive is my girlfriend of five years behaviour since this started. At first she was very concerned, showing it with a lot of physical affection. That didn't last long, gradually she's withdrawn from me more and more. Now she pulls away if I try to touch or kiss her. She finds excuses not to go out in public with me. She won't even sleep in the same bed as me anymore, always has a silly reason why. When I confronted her about those things she said she still loves me but that the 'watermelon dangling between your legs' grosses her out  and that she's embarrassed to e seen with me. That really was a slap in the face.

How do I deal with that? Feeling really low.