I just wanted to say about that I agree with the poster who mentions about men not liking it when women send the first message. I actually agree with this. I'm did some online dating last year and was sent well over 5000 messages which must prove I'm attractive, interesting and men want to get to know me. Yet the few dozen messages I sent when I first started were always ignored. It's quite strange actually.
That said, there was one guy who kept looking at my profile and but never messaged me, and in the end I messaged him. It turns out he didn't want to message me because he lived abroad a lot of the time and my profile said I wasn't interested in long-distance. And yes, you guessed it, we got together!
I also think you need to find some time to take a far more approachable picture. You're pretty but you're not highlighting this particularly well. Men are highly visual. For the most part, they just look at pictures, your age and often don't bother to even read a single word you've written before messaging you.
I first used GSM when it first started years and years ago. The quality of men back then was infinitely better and I met some great men. When I went back to online dating last year, I noticed the men on there were dreadful and seemed to be a terrible mix of sexist and Daily Mail type men almost as bad as those to be found on PoF, most of whom didn't want to date women who were remotely in the same age bracket as them. I don't use GSM anymore and won't be using it again.
I think you'll have far more luck on somewhere like OkCupid. Ok, you'll probably have to ignore a lot of dross but given your age, your outlook and that you like both men and women, I think you'll meet someone like minded.
Lastly, and most importantly, online dating is a numbers game and often a question of taking your time. Someone will turn up! Just relax, sit back and enjoy! (And laugh at the horrendous men who message you! I used to shout at the screen 'as if' in the manner of Cher from Clueless every time someone awful messaged me!)