Seems like you have a few options...
- Don't go out, and feel miserable
- Go out, and feel miserable
- Go out and have an awesome time!
Personally I'd aim for the third option.

I don't mean to be flippant here, I've been in very much the same situation in the past prior to transition. Going out with a group of women, being the only "guy" and hating it, wishing I could be seen and treated by them as one of the girls. It sucked big time. On those occasions I had such a rotten time I'm sure they wished they'd never asked me along, I was such a killjoy sad sack. But when I was able to relax and tell myself it wouldn't always be this way, that soon I'd be one of the girls too, then if could at least enjoy myself and not feel like a freak. Better to find a way to enjoy it - and seeing a light at the end of the tunnel, no matter how faint and far away, is better than being in a dark pit of misery. Hope you have a great night out!