Yeah, that did happen to me about three years ago. It was the result of a very vivid dream (like the one that showed me my name).
In it, I was walking in an abandoned city and, at the time, I was male-bodied. I saw a fight taking place in the ruins of an abandoned church, one that was semi-demolished and looked like it could fall down at any minute.
I say fight, but in reality it was several young, very frightened looking ladies backed into a corner, surrounded by a group of soldiers (at least that's what they looked like - although they were wearing appliances similar to gas masks).
Anyway, in muffled voices I could hear a constant stream of... sexual references as to what they were going to do to these women, and the delight they would take in doing so. This only made the women even more terrified and if they could have clawed through the wall, they would have ripped their fingers off trying.
Against my better judgement (that being "you really don't want to go over there, this isn't your fight") I approached the group. And then I noticed I was dressed in the same attire as these soldier guys.
One of the women spotted me and she shrank away even further, whereby the soldiers turned around and saluted. I have no idea why, but then they removed their masks and started...
*sigh*
Well, the remarks can't really be repeated here, but you could probably imagine what was said. Lots of comparisons with female dogs, female horses, slang terms for felines... and how they looked as though they were begging for a good... you know.
...
Anyway, that was when I started to feel very strange. I looked at the two groups repeatedly. But I couldn't move. I was like a rabbit frozen in the headlights of a car. I stared at my hands, then at the women, then at the soldiers.
And I felt disgusted. And horrified.
I said how abhorrent the soldiers' behaviour was (not exactly using that word or that turn of phrase *blushes*) and then removed the mask that I was wearing. This was when I caught sight of my reflection in the smashed glass of a nearby window. It definitely wasn't that of a male.
They were shocked for a second, then leering and wanting to know where "a piece like me got hold of a uniform."
The women were all staring at me as well, but their expressions were ones of solidarity and... hope almost. I felt connected to them, I felt like I belonged. And these soldier guys were a threat to us.
...
They forgot about the other women, and started to approach me with hideous grins on their faces. I admit that I was scared, but only partially with the threat of what they could do to me... also with the realisation of who I was and how I now felt totally disconnected to something I previously thought I was.
So, apparently my physical body had changed as well and I was, to all intents and purposes, a woman.
Just before I woke up, they all lunged at me and I removed two silver magnums from holsters that had somehow appeared at my sides, a-la Lara Croft, and sent them into the next life with those lecherous smiles still on their lips.
I walked towards the group of women, smiling, and felt... at home.
...
*blushes* Sorry for the long post, but that one dream, the vividness, the impact, changed my whole perception of how I see myself and my connection with my true gender. It's been like that ever since. I feel more of a kinship and deeper emotional connection with women, and that I am now one of the girls.