Hi dynamicbutler,
Sorry to hear things aren't working out that well, particularly with the fear during bondage.
From what it sounds like, your girlfriend and you are traveling where you perhaps haven't discussed. Would communication help out here at all? Have you ever expressed to her your desire to be dominated and what aspects you enjoy? The key to any power exchange is communication because it allays our fears, and can also give the dominant time to figure out in their mind how to best play with their submissive in a comfortable-for-all situation, particularly if it's new territory.
She may also need a little help... but I'm suspect there's a level of domme in her if she's tying you up and talking about strap-ons, granted her reactions need major work. Perhaps she's unaware that a man's g-spot is located internally, or that having her use a strap-on would be an intense submissive experience for you. Is it possible her reactions are due to inexperience?
I know your reticent to go speak to someone professional, but if you're reactions to bondage were that with someone you love and trust... most likely it's going to happen again. You seem very sincere in your desire to be submissive that maybe it's worth it to try and figure out how you can practice it without feeling uncomfortable.
Munches and such may be a great way for you to also see (particularly if it's a play dungeon) how other people react in situations, etc.
Best of luck to you!
cheers,
Orchidsoul