Miaou,
I'm sorry your first "Reiki" experience was not what you expected it to be. Yours is the type of account I am hearing a lot lately, in which people are expecting one thing and getting another, such as overly-lengthy sessions (a full session should take about an hour, in my opinion), odd feelings, mistrust, etc. It's too bad.
I'm not sure what to attribute these experiences to, but it seems like a lack of communication - and professionalism - is at the root of it all. If you felt like your session wasn't proceeding as you expected, then developing a level of trust with the practitioner was bound to be difficult. Know that you should feel free to end a session any time you want.
I understand the "male-female" issue and if you feel uncomfortable with a male working with you, then by all means, try a female. My first Reiki session was with a female practitioner and I felt like I was being "worked on" in a strange way... It actually turned me off of Reiki for quite a while. I found my way to it, though, and have studied and practiced and work to be the best I can be. I am a male practitioner and have had occasions when I could feel a pull from a female client. It isn't comfortable on that end, either.
I question some folks' intentions with healing work, and that's distressing to me. But Reiki is like anything else, and some will use it for their own purposes. Sometimes those purposes - and intentions - aren't the purest. Reiki won't stay in their hands for long and their "practice" will ultimately fail.
Trust your instincts. Do what feels right to you. It sounds like you are not turned off from Reiki and that's important! It is the best and I hope you stay with it.
Ken