Continuing with my series on how to survive as a geek girl in an XY world...
Feeling alienated in a male dominated industry is not unusual for women in IT. The main thing to remember is that you may feel unwelcome or uncomfortable but that doesn't mean you should leave. There are ways to find a place amongst the testosterone without changing who you are.
Geeks, nerds or whatever you choose to call us, have always respected one thing above all else and that is being good at what you do. It's what kept us alive during the dark high school years. That promise that we were good at logic, maths... stuff that the others sucked at and one day that would count for something. We still all respect that.
IT is one of the few meritocracies that I have seen in practice today. If you are good at what you do then you are respected. If you are great then you are celebrated. If you suck then you are rejected and ignored. This goes for men and women, young or old, black or white.
With women, being assertive and demanding respect is not something that we are encouraged to do so it doesn't feel natural. It's not part of our social makeup. Unfortunately, it is what the guys do when they are with other guys. They beat their chests to tell each other what they are good at and why you should respect them. I don't mean in a macho way at all. It's just a guy thing.
As a chick in IT you have to learn to do that. It doesn't have to be like the boys but it does have to be present. You must know when to show what you know and don't back down simply because it might bruise someones ego. That's ok. You are not their mum or their gf.
You have got here through the same degree they did. You work in the same places. You survive as a minority in a world that doesn't always encourage you. It's rigged against you so you simply existing here and now is proof that you mustn't suck.
Confidence is everything. It's a meritocracy so show your merit.